COVID-19 vaccine

See also: List of COVID-19 vaccine authorizations

Share of people who received at least one dose of COVID-19 vaccine

Map of countries by approval status

  Approved for general use, mass vaccination underway

  EUA (or equivalent) granted, mass vaccination underway

  EUA granted, limited vaccination

  Approved for general use, mass vaccination planned

  EUA granted, mass vaccination planned

  EUA pending

  No data available

A vaccination center in Brussels, Belgium

A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 (COVID‑19). Prior to the COVID‑19 pandemic, an established body of knowledge existed about the structure and function of coronaviruses causing diseases like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). This knowledge accelerated the development of various vaccine technologies during early 2020. The initial focus of SARS-CoV-2 vaccines was on preventing symptomatic, often severe illness. On 10 January 2020, the SARS-CoV-2 genetic sequence data was shared through GISAID, and by 19 March, the global pharmaceutical industry announced a major commitment to address COVID-19. The COVID‑19 vaccines are widely credited for their role in reducing the spread, severity, and death caused by COVID-19.

In Phase III trials, several COVID‑19 vaccines have demonstrated efficacy as high as 95% in preventing symptomatic COVID‑19 infections. Twenty vaccines are authorized by at least one national regulatory authority for public use: two RNA vaccines (Pfizer–BioNTech and Moderna), nine conventional inactivated vaccines (BBIBP-CorV, Chinese Academy of Medical Sciences, CoronaVac, Covaxin, CoviVac, COVIran Barakat, Minhai-Kangtai, QazVac, and WIBP-CorV), five viral vector vaccines (Sputnik Light, Sputnik V, Oxford–AstraZeneca, Convidecia, and Janssen), and four protein subunit vaccines (Abdala, EpiVacCorona, MVC-COV1901, Soberana 02, and ZF2001). In total, 330 vaccine candidates are in various stages of development, with 102 in clinical research, including 30 in Phase I trials, 30 in Phase I-II trials, 25 in Phase III trials, and 8 in Phase IV development.

Many countries have implemented phased distribution plans that prioritize those at highest risk of complications, such as the elderly, and those at high risk of exposure and transmission, such as healthcare workers. Single dose interim use is under consideration to extend vaccination to as many people as possible until vaccine availability improves.

As of 28 July 2021, 4.01 billion doses of COVID‑19 vaccine have been administered worldwide based on official reports from national public health agencies. AstraZeneca anticipates producing 3 billion doses in 2021, Pfizer–BioNTech 1.3 billion doses, and Sputnik V, Sinopharm, Sinovac, and Janssen 1 billion doses each. Moderna targets producing 600 million doses and Convidecia 500 million doses in 2021. By December 2020, more than 10 billion vaccine doses had been preordered by countries, with about half of the doses purchased by high-income countries comprising 14% of the world's population. CoronaVac (Sinovac) is the most widely used vaccine in the world, with over 943 million doses delivered globally.

Background

A CDC Fact sheet about COVID-19 vaccines

A US airman receiving a COVID-19 vaccine

Prior to COVID‑19, a vaccine for an infectious disease had never been produced in less than several years – and no vaccine existed for preventing a coronavirus infection in humans. However, vaccines have been produced against several animal diseases caused by coronaviruses, including (as of 2003) infectious bronchitis virus in birds, canine coronavirus, and feline coronavirus. Previous projects to develop vaccines for viruses in the family Coronaviridae that affect humans have been aimed at severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Vaccines against SARS and MERS have been tested in non-human animals.

According to studies published in 2005 and 2006, the identification and development of novel vaccines and medicines to treat SARS was a priority for governments and public health agencies around the world at that time. There is no cure or protective vaccine proven to be safe and effective against SARS in humans. There is also no proven vaccine against MERS. When MERS became prevalent, it was believed that existing SARS research might provide a useful template for developing vaccines and therapeutics against a MERS-CoV infection. As of March 2020, there was one (DNA-based) MERS vaccine which completed Phase I clinical trials in humans, and three others in progress, all being viral-vectored vaccines: two adenoviral-vectored (ChAdOx1-MERS, BVRS-GamVac) and one MVA-vectored (MVA-MERS-S).

Vaccine types

Conceptual diagram showing three vaccine types for forming SARS‑CoV‑2 proteins to prompt an immune response: (1) RNA vaccine, (2) subunit vaccine, (3) viral vector vaccine

Vaccine platforms being employed for SARS-CoV-2. Whole virus vaccines include both attenuated and inactivated forms of the virus. Protein and peptide subunit vaccines are usually combined with an adjuvant in order to enhance immunogenicity. The main emphasis in SARS-CoV-2 vaccine development has been on using the whole spike protein in its trimeric form, or components of it, such as the RBD region. Multiple non-replicating viral vector vaccines have been developed, particularly focused on adenovirus, while there has been less emphasis on the replicating viral vector constructs.

At least nine different technology platforms are under research and development to create an effective vaccine against COVID‑19. Most of the platforms of vaccine candidates in clinical trials are focused on the coronavirus spike protein and its variants as the primary antigen of COVID‑19 infection. Platforms being developed in 2020 involved nucleic acid technologies (nucleoside-modified messenger RNA and DNA), non-replicating viral vectors, peptides, recombinant proteins, live attenuated viruses, and inactivated viruses.

Many vaccine technologies being developed for COVID‑19 are not like vaccines already in use to prevent influenza, but rather are using "next-generation" strategies for precise targeting of COVID‑19 infection mechanisms. Several of the synthetic vaccines use a 2P mutation to lock the spike protein into its prefusion configuration, stimulating an immune response to the virus before it attaches to a human cell. Vaccine platforms in development may improve flexibility for antigen manipulation, and effectiveness for targeting mechanisms of COVID‑19 infection in susceptible population subgroups, such as healthcare workers, the elderly, children, pregnant women, and people with weakened immune systems.

RNA vaccines

Diagram of the operation of an RNA vaccine. Messenger RNA contained in the vaccine enters cells and is translated into foreign proteins, which trigger an immune response.

An RNA vaccine contains RNA which, when introduced into a tissue, acts as messenger RNA (mRNA) to cause the cells to build the foreign protein and stimulate an adaptive immune response which teaches the body how to identify and destroy the corresponding pathogen or cancer cells. RNA vaccines often, but not always, use nucleoside-modified messenger RNA. The delivery of mRNA is achieved by a coformulation of the molecule into lipid nanoparticles which protect the RNA strands and help their absorption into the cells.

RNA vaccines were the first COVID‑19 vaccines to be authorized in the United Kingdom, the United States and the European Union. Authorized vaccines of this type are the Pfizer–BioNTech COVID-19 vaccine and the Moderna COVID-19 vaccine. The CVnCoV RNA vaccine from CureVac failed in clinical trails.

Severe allergic reactions are rare. In December 2020, 1,893,360 first doses of Pfizer–BioNTech COVID‑19 vaccine administration resulted in 175 cases of severe allergic reaction, of which 21 were anaphylaxis. For 4,041,396 Moderna COVID‑19 vaccine dose administrations in December 2020 and January 2021, only ten cases of anaphylaxis were reported. The lipid nanoparticles were most likely responsible for the allergic reactions.

Adenovirus vector vaccines

These vaccines are examples of non-replicating viral vector vaccines, using an adenovirus shell containing DNA that encodes a SARS‑CoV‑2 protein. The viral vector-based vaccines against COVID‑19 are non-replicating, meaning that they do not make new virus particles, but rather produce only the antigen which elicits a systemic immune response.

Authorized vaccines of this type are the Oxford–AstraZeneca COVID-19 vaccine, the Sputnik V COVID-19 vaccine, Convidecia, and the Janssen COVID-19 vaccine.

Convidecia and the Janssen COVID-19 vaccine are both one-shot vaccines which offer less complicated logistics and can be stored under ordinary refrigeration for several months.

Sputnik V uses Ad26 for its first dose, which is the same as Janssen's only dose, and Ad5 for the second dose, which is the same as Convidecia's only dose.

Inactivated virus vaccines

Inactivated vaccines consist of virus particles that have been grown in culture and then are killed using a method such as heat or formaldehyde to lose disease producing capacity, while still stimulating an immune response.

Authorized vaccines of this type are the Chinese CoronaVac, BBIBP-CorV, and WIBP-CorV; the Indian Covaxin; later this year the Russian CoviVac; and the Kazakhstani vaccine QazVac. Vaccines in clinical trials include the Valneva COVID-19 vaccine.

Subunit vaccines

Subunit vaccines present one or more antigens without introducing whole pathogen particles. The antigens involved are often protein subunits, but can be any molecule that is a fragment of the pathogen.

The two authorized vaccines of this type are the peptide vaccine EpiVacCorona and ZF2001. Vaccines with pending authorizations include the Novavax COVID-19 vaccine, Soberana 02 (a conjugate vaccine), and the Sanofi–GSK vaccine. The V451 vaccine was previously in clinical trials, which were terminated because it was found that the vaccine may potentially cause incorrect results for subsequent HIV testing.

Other types

Additional types of vaccines that are in clinical trials include virus-like particle vaccines, multiple DNA plasmid vaccines, at least two lentivirus vector vaccines, a conjugate vaccine, and a vesicular stomatitis virus displaying the SARS‑CoV‑2 spike protein.

Oral vaccines and intranasal vaccines are being developed and studied.

Scientists investigated whether existing vaccines for unrelated conditions could prime the immune system and lessen the severity of COVID‑19 infection. There is experimental evidence that the BCG vaccine for tuberculosis has non-specific effects on the immune system, but no evidence that this vaccine is effective against COVID‑19.

Formulation

As of September 2020, eleven of the vaccine candidates in clinical development use adjuvants to enhance immunogenicity. An immunological adjuvant is a substance formulated with a vaccine to elevate the immune response to an antigen, such as the COVID‑19 virus or influenza virus. Specifically, an adjuvant may be used in formulating a COVID‑19 vaccine candidate to boost its immunogenicity and efficacy to reduce or prevent COVID‑19 infection in vaccinated individuals. Adjuvants used in COVID‑19 vaccine formulation may be particularly effective for technologies using the inactivated COVID‑19 virus and recombinant protein-based or vector-based vaccines. Aluminum salts, known as "alum", were the first adjuvant used for licensed vaccines, and are the adjuvant of choice in some 80% of adjuvanted vaccines. The alum adjuvant initiates diverse molecular and cellular mechanisms to enhance immunogenicity, including release of proinflammatory cytokines.

Planning and development

Main article: History of COVID-19 vaccine development

Since January 2020, vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry and between governments.

Multiple steps along the entire development path are evaluated, including:

• the level of acceptable toxicity of the vaccine (its safety),
• targeting vulnerable populations,
• the need for vaccine efficacy breakthroughs,
• the duration of vaccination protection,
• special delivery systems (such as oral or nasal, rather than by injection),
• dose regimen,
• stability and storage characteristics,
• emergency use authorization before formal licensing,
• optimal manufacturing for scaling to billions of doses, and
• dissemination of the licensed vaccine.

Challenges

There have been several unique challenges with COVID‑19 vaccine development.

The urgency to create a vaccine for COVID‑19 led to compressed schedules that shortened the standard vaccine development timeline, in some cases combining clinical trial steps over months, a process typically conducted sequentially over years.

Timelines for conducting clinical research – normally a sequential process requiring years – are being compressed into safety, efficacy, and dosing trials running simultaneously over months, potentially compromising safety assurance. As an example, Chinese vaccine developers and the government Chinese Center for Disease Control and Prevention began their efforts in January 2020, and by March were pursuing numerous candidates on short timelines, with the goal to showcase Chinese technology strengths over those of the United States, and to reassure the Chinese people about the quality of vaccines produced in China.

The rapid development and urgency of producing a vaccine for the COVID‑19 pandemic may increase the risks and failure rate of delivering a safe, effective vaccine. Additionally, research at universities is obstructed by physical distancing and closing of laboratories.

Vaccines must progress through several phases of clinical trials to test for safety, immunogenicity, effectiveness, dose levels and adverse effects of the candidate vaccine. Vaccine developers have to invest resources internationally to find enough participants for Phase II–III clinical trials when the virus has proved to be a "moving target" of changing transmission rates across and within countries, forcing companies to compete for trial participants. Clinical trial organizers also may encounter people unwilling to be vaccinated due to vaccine hesitancy or disbelief in the science of the vaccine technology and its ability to prevent infection. As new vaccines are developed during the COVID‑19 pandemic, licensure of COVID‑19 vaccine candidates requires submission of a full dossier of information on development and manufacturing quality.

Organizations

Internationally, the Access to COVID-19 Tools Accelerator is a G20 and World Health Organization (WHO) initiative announced in April 2020. It is a cross-discipline support structure to enable partners to share resources and knowledge. It comprises four pillars, each managed by two to three collaborating partners: Vaccines (also called "COVAX"), Diagnostics, Therapeutics, and Health Systems Connector. The WHO's April 2020 "R&D Blueprint (for the) novel Coronavirus" documented a "large, international, multi-site, individually randomized controlled clinical trial" to allow "the concurrent evaluation of the benefits and risks of each promising candidate vaccine within 3–6 months of it being made available for the trial." The WHO vaccine coalition will prioritize which vaccines should go into Phase II and III clinical trials, and determine harmonized Phase III protocols for all vaccines achieving the pivotal trial stage.

National governments have also been involved in vaccine development. Canada announced funding for 96 research vaccine research projects at Canadian companies and universities, with plans to establish a "vaccine bank" that could be used if another coronavirus outbreak occurs, and to support clinical trials and develop manufacturing and supply chains for vaccines.

China provided low-rate loans to one vaccine developer through its central bank, and "quickly made land available for the company" to build production plants. Three Chinese vaccine companies and research institutes are supported by the government for financing research, conducting clinical trials, and manufacturing.

Great Britain formed a COVID‑19 vaccine task force in April 2020 to stimulate local efforts for accelerated development of a vaccine through collaborations of industry, universities, and government agencies. It encompassed every phase of development from research to manufacturing.

In the United States, the Biomedical Advanced Research and Development Authority (BARDA), a federal agency funding disease-fighting technology, announced investments to support American COVID‑19 vaccine development, and manufacture of the most promising candidates. In May 2020, the government announced funding for a fast-track program called Operation Warp Speed. By March 2021, BARDA had funded an estimated $19.3 billion in COVID-19 vaccine development.

Large pharmaceutical companies with experience in making vaccines at scale, including Johnson & Johnson, AstraZeneca, and GlaxoSmithKline (GSK), formed alliances with biotechnology companies, governments, and universities to accelerate progression towards effective vaccines.

History

This section is an excerpt from History of COVID-19 vaccine development[edit]

COVID‑19 vaccine research samples in a NIAID lab freezer (30 January 2020)

COVID-19's caused virus, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), was isolated in late 2019. Its genetic sequence was published on 11 January 2020, triggering an urgent international response to prepare for an outbreak and hasten development of a preventive COVID-19 vaccine. Since 2020, vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry and between governments. By June 2020, tens of billions of dollars were invested by corporations, governments, international health organizations, and university research groups to develop dozens of vaccine candidates and prepare for global vaccination programs to immunize against COVID‑19 infection. According to the Coalition for Epidemic Preparedness Innovations (CEPI), the geographic distribution of COVID‑19 vaccine development shows North American entities to have about 40% of the activity, compared to 30% in Asia and Australia, 26% in Europe, and a few projects in South America and Africa.

In February 2020, the World Health Organization (WHO) said it did not expect a vaccine against SARS‑CoV‑2 to become available in less than 18 months. Virologist Paul Offit commented that, in hindsight, the development of a safe and effective vaccine within 11 months was a remarkable feat. The rapidly growing infection rate of COVID‑19 worldwide during 2020 stimulated international alliances and government efforts to urgently organize resources to make multiple vaccines on shortened timelines, with four vaccine candidates entering human evaluation in March (see COVID-19 vaccine § Trial and authorization status).

On 24 June 2020, China approved the CanSino vaccine for limited use in the military, and two inactivated virus vaccines for emergency use in high-risk occupations. On 11 August 2020, Russia announced the approval of its Sputnik V vaccine for emergency use, though one month later only small amounts of the vaccine had been distributed for use outside of the phase 3 trial.

The Pfizer–BioNTech partnership submitted an Emergency Use Authorization (EUA) request to the U.S. Food and Drug Administration (FDA) for the mRNA vaccine BNT162b2 (active ingredient tozinameran) on 20 November 2020. On 2 December 2020, the United Kingdom's Medicines and Healthcare products Regulatory Agency (MHRA) gave temporary regulatory approval for the Pfizer–BioNTech vaccine, becoming the first country to approve the vaccine and the first country in the Western world to approve the use of any COVID‑19 vaccine. As of 21 December 2020, many countries and the European Union had authorized or approved the Pfizer–BioNTech COVID‑19 vaccine. Bahrain and the United Arab Emirates granted emergency marketing authorization for BBIBP-CorV, manufactured by Sinopharm. On 11 December 2020, the FDA granted an EUA for the Pfizer–BioNTech COVID‑19 vaccine. A week later, they granted an EUA for mRNA-1273 (active ingredient elasomeran), the Moderna vaccine.

On March 31, 2021, the Russian government announced that they had registered the first COVID‑19 vaccine for animals. Named Carnivac-Cov, it is an inactivated vaccine for carnivorous animals, including pets, aimed at preventing mutations that occur during the interspecies transmission of SARS-CoV-2.

In June 2021, a report revealed that the UB-612 vaccine, developed by the US-based COVAXX, was a venture initiated for profits by the Blackwater founder Erik Prince. In a series of text messages to Paul Behrends, the close associate recruited for the COVAXX project, Prince described the profit-making possibilities in selling the COVID‑19 vaccines. COVAXX provided no data from the clinical trials on safety or efficacy. The responsibility of creating distribution networks was assigned to an Abu Dhabi-based entity, which was mentioned as "Windward Capital" on the COVAXX letterhead but was actually Windward Holdings. The sole shareholder of the firm, which handled "professional, scientific and technical activities", was Erik Prince. In March 2021, COVAXX raised $1.35 billion in a private placement.

Trial and authorization status

Phase I trials test primarily for safety and preliminary dosing in a few dozen healthy subjects, while Phase II trials – following success in Phase I – evaluate immunogenicity, dose levels (efficacy based on biomarkers) and adverse effects of the candidate vaccine, typically in hundreds of people. A Phase I–II trial consists of preliminary safety and immunogenicity testing, is typically randomized, placebo-controlled, while determining more precise, effective doses. Phase III trials typically involve more participants at multiple sites, include a control group, and test effectiveness of the vaccine to prevent the disease (an "interventional" or "pivotal" trial), while monitoring for adverse effects at the optimal dose. Definition of vaccine safety, efficacy, and clinical endpoints in a Phase III trial may vary between the trials of different companies, such as defining the degree of side effects, infection or amount of transmission, and whether the vaccine prevents moderate or severe COVID‑19 infection.

A clinical trial design in progress may be modified as an "adaptive design" if accumulating data in the trial provide early insights about positive or negative efficacy of the treatment. Adaptive designs within ongoing Phase II–III clinical trials on candidate vaccines may shorten trial durations and use fewer subjects, possibly expediting decisions for early termination or success, avoiding duplication of research efforts, and enhancing coordination of design changes for the Solidarity trial across its international locations.

List of authorized and approved vaccines

Further information: List of COVID-19 vaccine authorizations

For COVID-19 vaccination policy by country, see Vaccination policy § Table.

National regulatory authorities have granted emergency use authorizations for fifteen vaccines. Six of those have been approved for emergency or full use by at least one WHO-recognized stringent regulatory authority. Biologic License Applications for the Pfizer–BioNTech and Moderna COVID‑19 vaccines have been submitted to the US Food and Drug Administration (FDA).

• 

  RNA vaccines

    Pfizer–BioNTech

    Moderna
• 

  Adenovirus vector vaccines

    Sputnik V

    Oxford–AstraZeneca

    Janssen

    Convidecia

    Sputnik Light
• 

  Inactivated virus vaccines

    Sinopharm (BBIBP)

    CoronaVac

    Covaxin

    Sinopharm (WIBP)

    Others
• 

  Subunit vaccines

    EpiVacCorona

    Zifivax

    Abdala

    Soberana 02

    Medigen (MVC)

Vaccines authorized for emergency use or approved for full use

Vaccine, developers/sponsors	Country of origin	Type (technology)	Doses, interval	Storage temperature	Pre-marketing study (participants)	Postmarketing study (participants)	Authorization
Oxford–AstraZeneca COVID-19 vaccine (Vaxzevria, Covishield) University of Oxford, AstraZeneca, CEPI	United Kingdom, Sweden	Adenovirus vector (ChAdOx1)	2 doses 4–12 weeks	2–8 °C	Phase III (30,000) Interventional; randomized, placebo-controlled study for efficacy, safety, and immunogenicity. Overall efficacy of 76% after the first dose and 81% after a second dose taken 12 weeks or more after the first. May 2020 – Aug 2021, Brazil (5,000), United Kingdom, India	Phase IV (10,000) Interventional, non-randomized Feb 2021 – Dec 2024, Denmark	Full (2) Emergency (170)
Pfizer–BioNTech COVID-19 vaccine (Comirnaty) BioNTech, Pfizer	Germany, United States	RNA (modRNA in lipid nanoparticles)	2 doses 3–4 weeks	−70±10 °C (ULT)	Phase III (43,998) Randomized, placebo-controlled. Positive results from an interim analysis were announced on 18 November 2020 and published on 10 December 2020 reporting an overall efficacy of 95%. Jul–Nov 2020, Germany, United States	Phase IV (10,000) Interventional, non-randomized Feb 2021 – Dec 2024, Denmark	Full (5) Emergency (114)
Janssen COVID-19 vaccine Janssen Vaccines (Johnson & Johnson), BIDMC	United States, Netherlands	Adenovirus vector (recombinant Ad26)	1 dose	2–8 °C	Phase III (40,000) Randomized, double-blinded, placebo-controlled Positive results from an interim analysis were announced on 29 January 2021. J&J reports an efficacy of 66% against mild and moderate symptoms, and 85% against severe symptoms. Further, the mild and moderate efficacy ranged from 64% in South Africa to 72% in the United States. Jul 2020 – ? 2023, United States, Argentina, Brazil, Chile, Colombia, Mexico, Peru, the Philippines, South Africa, Ukraine		Full (2) Emergency (85)
Moderna COVID-19 vaccine (Spikevax) Moderna, NIAID, BARDA, CEPI	United States	RNA (modRNA in lipid nanoparticles)	2 doses 4 weeks	−20±5 °C (freezer)	Phase III (30,000) Interventional; randomized, placebo-controlled study for efficacy, safety, and immunogenicity. Positive results from an interim analysis were announced on 15 November 2020 and published on 30 December 2020 reporting an overall efficacy of 94%. Jul 2020 – Oct 2022, United States	Phase IV (10,000) Interventional, non-randomized Feb 2021 – Dec 2024, Denmark	Full (1) Emergency (86)
BBIBP-CorV Sinopharm: Beijing Institute of Biological Products	China	Inactivated SARS‑CoV‑2 (vero cells)	2 doses 3–4 weeks	2–8 °C	Phase III (48,000) Randomized, double-blind, parallel placebo-controlled, to evaluate safety and protective efficacy. Peer-reviewed results indicate 78.1% efficacy against symptomatic COVID-19. Jul 2020 – Jul 2021, United Arab Emirates, Bahrain, Jordan, Argentina, Morocco, Peru		Full (4) Emergency (79)
Sputnik V COVID-19 vaccine (Gam-COVID-Vac) Gamaleya Research Institute of Epidemiology and Microbiology	Russia	Adenovirus vector (recombinant Ad5 and Ad26)	2 doses 3 weeks	≤−18 °C (freezer)	Phase III (40,000) Randomized double-blind, placebo-controlled to evaluate efficacy, immunogenicity, and safety. Interim analysis from the trial was published in The Lancet, indicating 91.6% efficacy without unusual side effects. Aug 2020 – May 2021, Russia, Belarus, India, Venezuela, United Arab Emirates		Full (2) Emergency (72)
CoronaVac Sinovac	China	Inactivated SARS‑CoV‑2 (vero cells)	2 doses 2–4 weeks	2–8 °C	Phase III (33,620) Double-blind, randomized, placebo-controlled to evaluate efficacy and safety. Peer-reviewed Phase III results from Turkey showed an efficacy of 83.5%. A Chilean study showed 65% efficacy against symptomatic cases, 87% against hospitalization, 90% against ICU admissions, and 86% against deaths. Brazil announced results showing 50.7% effective at preventing symptomatic infections, 83.7% effective in preventing mild cases, and 100% effective in preventing severe cases. July 2020 – Oct 2021, Brazil (15,000); Aug 2020 – January 2021, Indonesia (1,620); Oct – Nov 2020, China (1,040); Nov 2020 – Jan 2022, Chile (3,000); Apr 2021 – Jun 2022, the Philippines (phase II/III: 352); Sep 2020 – Feb 2021, Turkey (13,000);	Phase IV (37,867) Interventional Feb 2021 – Feb 2022, Serrana (São Paulo) (27,711); Mar 2021 – Mar 2022, Manaus (10,156)	Full (1) Emergency (54)
Covaxin Bharat Biotech, Indian Council of Medical Research	India	Inactivated SARS‑CoV‑2 (vero cells)	2 doses 4 weeks	2–8 °C	Phase III (25,800) Randomised, observer-blinded, placebo-controlled Bharat Biotech reported an interim efficacy is 78% for its phase 3 trial. Nov 2020 – Mar 2021, India.	Phase IV (1,000) Interventional, non-randomized July 2021 – Dec 2021, India	Full (0) Emergency (21)
Sputnik Light Gamaleya Research Institute of Epidemiology and Microbiology	Russia	Adenovirus vector (recombinant Ad26)	1 dose	2–8 °C	Phase III (7,000) Randomised, double-blind, placebo-controlled trial Feb  – Dec 2021, Russia (6,000)		Full (0) Emergency (12)
Convidecia CanSino Biologics, Beijing Institute of Biotechnology of the Academy of Military Medical Sciences	China	Adenovirus vector (recombinant Ad5)	1 dose	2–8 °C	Phase III (40,000) Global multi-center, randomized, double-blind, placebo-controlled to evaluate efficacy, safety and immunogenicity. In February 2021, interim analysis from global trials showed an efficacy of 65.7% against symptomatic cases of COVID-19 and 90.98% efficacy against severe cases. Mar–Dec 2020, China; Sep 2020 – Dec 2021, Pakistan; Sep–Nov 2020, Russia, China, Argentina, Chile; Mexico; Pakistan; Saudi Arabia		Full (1) Emergency (8)
WIBP-CorV Sinopharm: Wuhan Institute of Biological Products	China	Inactivated SARS‑CoV‑2 (vero cells)	2 doses 3 weeks	2–8 °C	Phase III (51,600) Randomized, double-blind, placebo-controlled Peer-reviewed results indicate 72.8% efficacy against symptomatic COVID-19. Jul 2020 – Mar 2021, Bahrain, Egypt, Jordan, United Arab Emirates; Sep 2020 – Sep 2021, Peru; Sep 2020 – Dec 2020, Morocco		Full (1) Emergency (4)
EpiVacCorona Vector Institute	Russia	Subunit (peptide)	2 doses 3 weeks	2–8 °C	Phase III (40,150(planned), 3,000(started)) Randomized double-blind, placebo-controlled to evaluate efficacy, immunogenicity, and safety Nov 2020 – Dec 2021, Russia (3,000)		Full (1) Emergency (2)
ZF2001 (ZIFIVAX) Anhui Zhifei Longcom Biopharmaceutical Co. Ltd.	China	Subunit (recombinant)	3 doses 30 days	2–8 °C	Phase III (29,000) Randomized, double-blind, placebo-controlled Dec 2020 – Apr 2022, China, Ecuador, Indonesia, Malaysia, Pakistan, Uzbekistan		Full (0) Emergency (2)
Abdala BioCubaFarma, Center for Genetic Engineering and Biotechnology	Cuba	Subunit	3 doses 2 weeks	2–8 °C	Phase III (48,290) Multicenter, randomized, double-blind, placebo-controlled. Mar–Jul 2021, Cuba		Full (0) Emergency (2)
CoviVac The Chumakov Centre at the Russian Academy of Sciences	Russia	Inactivated SARS‑CoV‑2 (vero cells)	2 doses 2 weeks	2–8 °C	Phase III (32,000) Double-blind, randomized, placebo-controlled to evaluate efficacy and safety. May 2021 – ?, Russia (3,000)		Full (0) Emergency (1)
QazCovid-in (QazVac) Research Institute for Biological Safety Problems	Kazakhstan	Inactivated SARS‑CoV‑2	2 doses 3 weeks	2–8 °C	Phase III (3,000) Randomised, blind, placebo-controlled trial Mar 2021 – Jul 2021, Kazakhstan		Full (0) Emergency (1)
Minhai COVID-19 vaccine (KCONVAC) Minhai Biotechnology Co., Shenzhen Kangtai Biological Products Co. Ltd.	China	Inactivated SARS‑CoV‑2 (vero cell)	2 doses 4 weeks	2–8 °C	Phase III (28,000) Multi-national, Randomized, Double-blind, Placebo-controlled. April–Nov 2021, China, Malaysia, the Philippines		Full (0) Emergency (1)
COVIran Barakat (COVIRAN) Barakat Pharmaceutical Group, Shifa Pharmed Industrial Group	Iran	Inactivated SARS‑CoV‑2	2 doses 4 weeks	2–8 °C	Phase III (30,500) Phase II-IIIa (20,000): Randomized, double-blind, parallel arms, placebo-controlled. Phase IIIb (10,500) Mar–Jun 2021, Iran		Full (0) Emergency (1)
Chinese Academy of Medical Sciences COVID-19 vaccine (Covidful) Chinese Academy of Medical Sciences, Institute of Medical Biology	China	Inactivated SARS‑CoV‑2	2 doses 2 weeks	2–8 °C	Phase III (34,020) Randomized, double-blinded, single-center, placebo-controlled Jan–Sep 2021, Brazil, Malaysia		Full (0) Emergency (1)
Soberana 02 (FINLAY-FR-2) BioCubaFarma, Instituto Finlay de Vacunas	Cuba	Subunit (conjugate)	2 doses 4 weeks	2–8 °C	Phase III (44,010) Multicenter, adaptive, parallel-group, randomized, placebo-controlled, double-blind Mar–May 2021, Cuba, Iran, Venezuela		Full (0) Emergency (1)
MVC COVID-19 vaccine (MVC-COV1901) Medigen Vaccine Biologics, Dynavax Technologies	Taiwan	Subunit (S-2P protein +CpG 1018)			Phase II (4,152) Phase IIa (3,752): Prospective, double-blinded, multi-center, multi-regional. Phase IIb (400): Prospective, randomized, double-blind, dose-comparison, multi-center. Dec 2020 – Sep 2021, Taiwan, Vietnam (phase IIa)		Full (0) Emergency (1)

Vaccine candidates in human trials

COVID‑19 candidate vaccines in Phase I–III trials

Vaccine candidates, developers, and sponsors	Country of origin	Type (technology)	Current phase (participants) design	Completed phase (participants) Immune response	Pending authorization
Novavax COVID-19 vaccine (Covovax) Novavax, CEPI	United States	Subunit/virus-like particle (SARS‑CoV‑2 recombinant spike protein nanoparticle with adjuvant)	Phase III (48,000) Randomised, observer-blinded, placebo-controlled trial Sep 2020 – Jan 2021, UK (15,000); Dec 2020 – Jun 2023, US, Mexico, (33,000); India	Phase I–II (131) IgG and neutralizing antibody response with adjuvant after booster dose.	Emergency (8) Canada EU Ukraine USA UK Australia New Zealand South Korea
Sanofi–GSK COVID-19 vaccine (VAT00008, Vidprevtyn) Sanofi Pasteur, GSK	France, United Kingdom	Subunit (SARS-CoV-2 S adjuvanted recombinant protein)	Phase III (37,430) A Parallel-group, Phase III, Multi-stage, Modified Double-blind, Multi-armed Study to Assess the Efficacy, Safety, and Immunogenicity of Two SARS-CoV-2 Adjuvanted Recombinant Protein Vaccines (Monovalent and Bivalent) for Prevention Against COVID-19 in Adults 18 Years of Age and Older. May 2021 – Jan 2023, Honduras, Japan, Kenya, Mexico, United States	Phase I–II (1,160) Phase I-IIa (440): Immunogenicity and Safety of SARS-CoV-2 Recombinant Protein Vaccine Formulations (With or Without Adjuvant) in Healthy Adults 18 Years of Age and Older. Phase IIb (720): Immunogenicity and Safety of SARS-CoV-2 Recombinant Protein Vaccine With AS03 Adjuvant in Adults 18 Years of Age and Older. Sep 2020 – Apr 2022, United States	Emergency (4) EU Canada USA UK
CureVac COVID-19 vaccine (CVnCoV) CureVac, CEPI	Germany	RNA (unmodified RNA)	Phase III (44,433) Phase 2b/3 (39,693): Multicenter efficacy and safety trial in adults. Phase 3 (2,360+180+1,200+1,000=4,740): Randomized, observer-blinded, placebo-controlled, open-label, multicenter. Nov 2020 – Nov 2021, Argentina, Belgium, Colombia, Dominican Republic, France, Germany, Mexico, Netherlands, Panama, Peru, Spain	Phase I–II (944) Phase I (284): Partially blind, controlled, dose-escalation to evaluate safety, reactogenicity and immunogenicity. Phase IIa (660):Partially observer-blind, multicenter, controlled, dose-confirmation. Jun 2020 – Oct 2021, Belgium (phase I), Germany (phase I), Panama (phase IIa), Peru (phase IIa)	Emergency (2) EU Switzerland
CoVLP Medicago, GSK	Canada, United Kingdom	Virus-like particles (recombinant, plant-based with AS03)	Phase III (30,918) Event-driven, randomized, observer blinded, placebo-controlled Nov 2020 – Dec 2021, Brazil, Canada, United Kingdom, United States	Phase I (180) Neutralizing antibodies at day 42 after the first injection (day 21 after the second injection) were at levels 10x that of COVID-19 survivors. Jul 2020 – Sept 2021, Canada	Emergency (1) Canada
Valneva COVID-19 vaccine Valneva	France	Inactivated SARS‑CoV‑2	Phase III (4,769) Phase III (4,019+750): Randomized, observer-blind, controlled, non-inferiority. Apr–Dec 2021, New Zealand, United Kingdom	Phase I–II (3,039) Phase I/II (153): Randomized, multi-center, double-blinded. Phase II (2,886): A randomised, phase II UK multi-centre study to determine reactogenicity and immunogenicity of booster vaccination against ancestral and novel variants of SARS-CoV-2. Dec 2020 – Jun 2021, United Kingdom	Emergency (1) EU
ZyCoV-D Cadila Healthcare, Biotechnology Industry Research Assistance Council	India	DNA (plasmid expressing SARS‑CoV‑2 S protein)	Phase III (28,216) Randomised, blind, placebo-controlled trial Jan–May 2021, India	Phase I–II (1,000) Interventional; randomized, double-blind, placebo-controlled Jul 2020 – Jan 2021, India	Emergency (1) India
Nanocovax Nanogen Pharmaceutical Biotechnology JSC	Vietnam	Subunit (SARS‑CoV‑2 recombinant spike protein with aluminum adjuvant)	Phase III (13,000) Adaptive, multicenter, randomized, double-blind, placebo-controlled Jun 2021 – Jul 2022, Vietnam	Phase I–II (620) Phase I (60): Open label, dose escalation. Phase II (560): Randomization, double-blind, multicenter, placebo-controlled. Dec 2020 – Jun 2021, Vietnam	Emergency (1) Vietnam
UB-612 United Biomedical,Inc, Vaxxinity, DASA	Brazil, United States	Subunit (Multitope peptide based S1-RBD-protein based vaccine)	Phase III (18,320) Phase IIb/III (7,320): Randomized, Multicenter, Double-Blind, Placebo Controlled, Dose-Response. Phase III (11,000) Jan 2021 – Mar 2023, Taiwan (phase 2b/3), India (phase 3)	Phase I–II (3,910) Phase 1 (60): Open-label study Phase IIa (3,850): Placebo-controlled, Randomized, Observer-blind Study. Sep 2020 – Jan 2021, Taiwan	Emergency (1) Taiwan
TURKOVAC Health Institutes of Turkey	Turkey	Inactivated SARS‑CoV‑2	Phase III (40,800) Randomized, double-blinded, multi-center, active-controlled. Jun 2021 – Sep 2022, Turkey	Phase I–II (294) Phase I (44): Study for the Determination of Safety and Immunogenicity of Two Different Strengths of the Inactivated COVID-19 Vaccine ERUCOV-VAC, Given Twice Intramuscularly to Healthy Volunteers, in a Placebo Controlled Study Design. Phase 2 (250): Study for the Determination of Efficacy, Immunogenicity and Safety of Two Different Strengths of the Inactivated COVID-19 Vaccine ERUCOV-VAC, in a Placebo Controlled, Randomized, Double Blind Study Design. Nov 2020 – Apr 2021, Turkey
West China Hospital COVID-19 vaccine Jiangsu Province Centers for Disease Control and Prevention, West China Hospital, Sichuan University	China	Subunit (recombinant with Sf9 cell)	Phase III (40,000) Multicenter, randomized, double-blind, placebo-controlled. Jun 2021 – Feb 2022, China, the Philippines	Phase I–II (5,005) Phase I (45): Single-center, Randomized, Placebo-controlled, Double-blind. Phase IIa (960):Single-center, Randomized, Double-Blinded, Placebo-Controlled. Phase IIb (4,000):Single-center, Randomized, Double-Blinded, Placebo-Controlled. Aug 2020 – May 2021, China
SCB-2019 Clover Biopharmaceuticals, Dynavax Technologies, CEPI	China	Subunit (spike protein trimeric subunit with combined CpG 1018 and aluminium adjuvant)	Phase III (29,000) Phase II/III: Randomized, double-blind, controlled Mar  – Jul 2021, Belgium, Brazil, Colombia, Dominican Republic, Germany, Nepal, Panama, the Philippines, Poland, South Africa	Phase I–II (950) Phase I (150): Randomized, Double-blind, Placebo-controlled, First-in-human. Phase II (800): Multi-center, Double-blind, Randomized, Controlled. Jun 2020 – Oct 2021, Australia (phase 1), China (phase 2)
Walvax COVID-19 vaccine (ARCoV) PLA Academy of Military Science, Walvax Biotech, Suzhou Abogen Biosciences	China	RNA	Phase III (28,000) Multi-center, Randomized, Double-blind, Placebo-controlled May–Oct 2021, China, Malaysia, Mexico	Phase I–II (588) Phase I (168) Phase II (420) Jun 2020 – Mar 2022, China
Bio E COVID-19 (Corbevax) Biological E. Limited, Baylor College of Medicine, CEPI	India, United States	Subunit (using an antigen)	Phase III (1,268) Phase 2b/3: Single Arm, Prospective, multicentre. Apr – Aug 2021, India	Phase I–II (360) Randomized, Parallel Group Trial Nov 2020 – Feb 2021, India
GRAd-COV2 ReiThera, Lazzaro Spallanzani National Institute for Infectious Diseases	Italy	Adenovirus vector (modified gorilla adenovirus vector, GRAd)	Phase II–III (10,300) Randomized, stratified, observer-blind, placebo-controlled. Mar–May 2021, Italy	Phase I (90) Subjects (two groups: 18–55 and 65–85 years old) randomly receiving one of three escalating doses of GRAd-COV2 or a placebo, then monitored over a 24-week period. 93% of subjects who received GRAd-COV2 developed anti-bodies. Aug–Dec 2020, Rome
Inovio COVID-19 Vaccine (INO-4800) Inovio, CEPI, Korea National Institute of Health, International Vaccine Institute	South Korea, United States	DNA vaccine (plasmid delivered by electroporation)	Phase II–III (6,578) Phase II/III (6,578): Randomized, placebo-controlled, multi-center. Nov 2020 – Sep 2022, United States (phase II/III)	Phase I–II (920) Phase Ia (120): Open-label trial. Phase Ib-IIa (160): Dose-Ranging Trial. Phase II (640): Randomized, double-blinded, placebo-controlled, dose-finding. April 2020 – Feb 2022, China (phase II), South Korea (phase Ib-IIa), United States
AG0302-COVID‑19 AnGes Inc., AMED	Japan	DNA vaccine (plasmid)	Phase II–III (500) Randomized, double-blind, placebo controlled Nov 2020 – Apr 2021, Japan	Phase I–II (30) Randomized/non-randomized, single-center, two doses Jun–Nov 2020, Osaka
V-01 Livzon Mabpharm, Inc.	China	Subunit (SARS-CoV-2 recombinant fusion protein)	Phase II (880) Randomized, double-blind, and placebo-controlled. Mar–May 2021, China	Phase I (180) Single-center, randomized, double-blind and placebo-controlled. Feb–Mar 2021, China
DelNS1-2019-nCoV-RBD-OPT (DelNS1-nCoV-RBD LAIV) Beijing Wantai Biological Pharmacy, University of Hong Kong	China, Hong Kong	Replicating Viral vector (flu-based-RBD)	Phase II (720) Nov 2020 – Dec 2021, China	Phase I (60) Sep 2020 – Oct 2021, China
Razi Cov Pars Razi Vaccine and Serum Research Institute	Iran	Subunit (Recombinant Spike protein)	Phase II (500) Two parallel groups, randomized, double blind, placebo controlled. Apr–Jun 2021, Iran	Phase I (133) Randomized, double blind, placebo controlled. Jan–Mar 2021, Iran
FAKHRAVAC (MIVAC) Organization of Defensive Innovation and Research	Iran	Inactivated SARS‑CoV‑2	Phase II (500) Randomized, double blind, controlled trial with parallel design. Jun–Jul 2021, Iran	Phase I (135) Randomized, double blind, controlled trial with factorial design. Mar–Apr 2021, Iran
Zhongyianke Biotech–Liaoning Maokangyuan Biotech COVID-19 vaccine Zhongyianke Biotech, Liaoning Maokangyuan Biotech, Academy of Military Medical Sciences	China	Subunit (SARS-CoV-2 neutralizing antibody and the recombinant S-RBD protein specific antibody)	Phase II (480) Single-center, randomized, double blinded, placebo controlled. Mar–Jul 2021, China	Phase I (216) Randomized, placebo-controlled, double-blind. Oct 2020 – Apr 2021, China
COVAX-19 (SpikoGen) Vaxine Pty Ltd, Cinnagen	Australia, Iran	Subunit (recombinant protein)	Phase II (400) Randomized, Two-armed, Double-blind, Placebo controlled. May – Jul 2021, Iran	Phase I (40) Jun 2020 – Feb 2021, Adelaide
Unnamed Ihsan Gursel, Scientific and Technological Research Council of Turkey	Turkey	Virus-like particle	Phase II (330) Randomized, parallel dose assigned, double blind, multi center. Jun – Sep 2021, Turkey	Phase I (36) double-blinded, randomised, placebo controlled. Mar – May 2021, Turkey
COH04S1 City of Hope Medical Center	United States	Viral vector	Phase II (240) Multi-center, observer-blinded, EUA vaccine-controlled, randomized. Aug 2021 – Jun 2023, California	Phase I (129) Dose Escalation Study. Dec 2020 – Nov 2022, California
SCB-2020S Clover Biopharmaceuticals	China	Subunit	Phase I–II (150) Randomized, controlled, observer-blind. Aug–Oct 2021, Australia	Preclinical
Unnamed National Vaccine and Serum Institute, Lanzhou Institute of Biological Products Co., Ltd., Beijing Zhong Sheng Heng Yi Pharmaceutical Technology Co., Ltd., Zhengzhou University	China	Subunit (Recombinant)	Phase I–II (3,580) Phase I/II Clinical Trial to Evaluate the Safety, Tolerability and Immunogenicity of Recombinant SARS-CoV-2 Vaccine (CHO Cell) in Healthy People Aged 3 Years and Older. Apr 2021 – Oct 2022, China	Preclinical
BriLife (IIBR-100) The Israel Institute for Biological Research	Israel	Vesicular stomatitis vector (recombinant)	Phase I–II (1,040) Oct 2020 – May 2021, Israel	Preclinical
Arcturus COVID-19 vaccine (ARCT-021) Arcturus Therapeutics, Duke–NUS Medical School	United States, Singapore	RNA	Phase I–II (798) Phase I/II (92): Randomized, double-blinded, placebo controlled Phase IIa (106+600): Open label extension, randomized, observer-blind, placebo-controlled. Aug 2020 – Apr 2022, Singapore, United States (phase IIa)	Preclinical
VBI-2902 Variation Biotechnologies	United States	Virus-like particle	Phase I–II (780) Randomized, observer-blind, dose-escalation, placebo-controlled Mar 2021 – Jun 2022, Canada	Preclinical
NDV-HXP-S (ButanVac, COVIVAC, HXP-GPOVac, Patria) Institute of Vaccines and Medical Biologicals, Butantan Institute, Laboratorio Avimex, National Council of Science and Technology, Mahidol University, University of Texas at Austin,	Brazil, Mexico, Thailand, United States, Vietnam	Newcastle disease virus (NDV) vector (expressing the spike protein of SARS-CoV-2, with or without the adjuvant CpG 1018)	Phase I–II (460) Randomized, placebo-controlled, observer-blind. Mar 2021 – May 2022; Brazil, Mexico, Thailand, Vietnam	Preclinical
Sanofi–Translate Bio COVID-19 vaccine (MRT5500) Sanofi Pasteur and Translate Bio	France, United States	RNA	Phase I–II (415) Immunogenicity and Safety of the First-in-Human SARS-CoV-2 mRNA Vaccine Formulation in Healthy Adults 18 Years of Age and Older. Mar 2021 – Sep 2022, Honduras, United States	Preclinical
EuCorVac-19 EuBiologics Co	South Korea	Subunit (spike protein using the recombinant protein technology and with an adjuvant)	Phase I–II (280) Dose-exploration, randomized, observer-blind, placebo-controlled Feb 2021 – Mar 2022, the Philipppines (phase II), South Korea (phase I/II)	Preclinical
RBD SARS-CoV-2 HBsAg VLP SpyBiotech	United Kingdom	Virus-like particle	Phase I–II (280) Randomized, placebo-controlled, multi-center. Aug 2020 – ?, Australia	Preclinical
GX-19 (GX-19N) Genexine consortium, International Vaccine Institute	South Korea	DNA	Phase I–II (410) Phase I-II (170+210+30): Multi-center, open-label, single arm, randomized, double-blind, placebo-controlled Jun 2020 – Jul 2021, Seoul	Preclinical
AV-COVID-19 AIVITA Biomedical, Inc., Ministry of Health (Indonesia)	United States, Indonesia	Viral vector (Dendritic cell)	Phase I–II (202) Adaptive. Dec 2020 – Feb 2022, Indonesia (phase I), United States (phase I/II)	Preclinical
COVID-eVax Takis Biotech	Italy	DNA	Phase I–II (160) Phase I:First-in-human, dose escalation. Phase II: Open-label, randomize, dose expansion. Feb–Sep 2021, Italy	Preclinical
ChulaCov19 Chulalongkorn University	Thailand	RNA	Phase I–II (96) Dose-finding Study. Jan–Mar 2021, Thailand	Preclinical
COVID‑19/aAPC Shenzhen Genoimmune Medical Institute	China	Lentiviral vector (with minigene modifying aAPCs)	Phase I (100) Mar 2020 – Jul 2023, Shenzhen	Preclinical
LV-SMENP-DC Shenzhen Genoimmune Medical Institute	China	Lentiviral vector (with minigene modifying DCs)	Phase I (100) Mar 2020 – Jul 2023, Shenzhen	Preclinical
ImmunityBio COVID-19 vaccine (hAd5) ImmunityBio	United States	Viral vector	Phase I–II (540) Phase 1/2 Study of the Safety, Reactogenicity, and Immunogenicity of a Subcutaneously- and Orally- Administered Supplemental Spike & Nucleocapsid-targeted COVID-19 Vaccine to Enhance T Cell Based Immunogenicity in Participants Who Have Already Received Prime + Boost Vaccines Authorized For Emergency Use. Oct 2020  – Sep 2021, South Africa, United States	Preclinical
HGC019 Gennova Biopharmaceuticals, HDT Biotech Corporation	India, United States	RNA	Phase I–II (620) Phase I (120) Phase II (500) Apr 2021 – ?, India	Preclinical
PTX-COVID19-B Providence Therapeutics	Canada	RNA	Phase I (60) First-in-Human, Observer-Blinded, Randomized, Placebo Controlled. Jan–May 2021, Canada	Preclinical
COVAC-2 VIDO (University of Saskatchewan)	Canada	Subunit (spike protein + SWE adjuvant)	Phase I (108) Randomized, observer-blind, dose-escalation. Feb 2021 – Oct 2022, Halifax	Preclinical
COVI-VAC (CDX-005) Codagenix Inc.	United States	Attenuated	Phase I (48) First-in-human, randomised, double-blind, placebo-controlled, dose-escalation Dec 2020 – Jun 2021, United Kingdom	Preclinical
CoV2 SAM (LNP) GSK	United Kingdom	RNA	Phase I (40) Open-label, dose escalation, non-randomized Feb–Jun 2021, United States	Preclinical
COVIGEN Bionet Asia, Technovalia, University of Sydney	Australia	DNA	Phase I (150) Double-blind, dose-ranging, randomised, placebo-controlled. Feb 2021 – Jun 2022, Australia, Thailand	Preclinical
BBV154 Bharat Biotech	India	Adenovirus vector (intranasal)	Phase I (175) Randomized, double-blinded, multicenter. Mar–Jun 2021, India	Preclinical
MV-014-212 Meissa Vaccine Inc.	United States	Attenuated	Phase I (130) Randomized, double-blinded, multicenter. Mar 2021 – Oct 2022, United States	Preclinical
S-268019 Shionogi	Japan	Subunit	Phase I–II (300) Randomized, double-blind, placebo-controlled, parallel-group. Dec 2020 – Jun 2022, Japan	Preclinical
GBP510 SK Bioscience Co. Ltd., GSK	South Korea	Subunit (Recombinant protein nanoparticle with adjuvanted with AS03)	Phase I–II (580) Phase I-II (260-320): Placebo-controlled, randomized, observer-blinded, dose-finding. Jan–Aug 2021, South Korea	Preclinical
KBP-201 Kentucky Bioprocessing	United States	Subunit	Phase I–II (180) First-in-human, observer-blinded, randomized, placebo-controlled, parallel group Dec 2020 – Jul 2021, United States	Preclinical
AdCLD-CoV19 Cellid Co	South Korea	Viral vector	Phase I–II (150) Phase I: Dose Escalation, Single Center, Open. Phase IIa: Multicenter, Randomized, Open. Dec 2020 – Mar 2021, South Korea	Preclinical
AdimrSC-2f Adimmune Corporation	Taiwan	Subunit (Recombinant RBD +/− Aluminium)	Phase I (70) Randomized, single center, open-label, dose-finding. Aug–Nov 2020, Taiwan	Preclinical
AKS-452 University Medical Center Groningen	Netherlands	Subunit	Phase I–II (130) Non-randomized, Single-center, open-label, combinatorial. Apr–Jun 2021, Netherlands	Preclinical
GLS-5310 GeneOne Life Science Inc.	South Korea	DNA	Phase I–II (345) Multicenter, Randomized, Combined Phase I Dose-escalation and Phase IIa Double-blind. Dec 2020 – Jul 2022, South Korea	Preclinical
Covigenix VAX-001 Entos Pharmaceuticals Inc.	Canada	DNA	Phase I–II (72) Placebo-controlled, randomized, observer-blind, dose ranging adaptive. Mar–Aug 2021, Canada	Preclinical
NBP2001 SK Bioscience Co. Ltd.	South Korea	Subunit (Recombinant protein with adjuvanted with alum)	Phase I (50) Placebo-controlled, Randomized, Observer-blinded, Dose-escalation. Dec 2020 – Apr 2021, South Korea	Preclinical
CoVac-1 University of Tübingen	Germany	Subunit	Phase I (36) Placebo-controlled, Randomized, Observer-blinded, Dose-escalation. Nov 2020 – Sep 2021, Germany	Preclinical
bacTRL-Spike Symvivo	Canada	DNA	Phase I (24) Randomized, observer-blind, placebo-controlled. Nov 2020 – Feb 2022, Australia	Preclinical
CORVax12 Providence Health & Services	United States	DNA	Phase I (36) Open-label. Dec 2020 – May 2021, United States	Preclinical
ChAdV68-S (SAM-LNP-S) NIAID, Gritstone Oncology	United States	Viral vector	Phase I (130) Open-label, dose and age escalation, parallel design. Mar 2021 – Sep 2022, United States	Preclinical
VXA-CoV2-1 (VXA-NVV-104) Vaxart	United States	Viral vector	Phase I (83) Phase Ia (35): Double-blind, randomized, placebo-controlled, first-in-Human. Phase Ib (48): Multicenter, randomized, double-blind, placebo-controlled. Sep 2020 – Aug 2021, United States	Preclinical
SpFN COVID-19 vaccine United States Army Medical Research and Development Command	United States	Subunit	Phase I (72) Randomized, double-blind, placebo-controlled. Apr 2021 – Oct 2022, United States	Preclinical
MVA-SARS-2-S (MVA-SARS-2-ST) University Medical Center Hamburg-Eppendorf	Germany	Viral vector	Phase I–II (270) Phase I (30): Open, Single-center. Phase Ib/IIa (240): Multi-center, Randomized Controlled. Oct 2020 – Mar 2022, Germany	Preclinical
ReCOV Jiangsu Rec-Biotechnology Co Ltd	China	Subunit (Recombinant two-component spike and RBD protein (CHO cell))	Phase I (160) First-in-human, randomized, double-blind, placebo-controlled, dose-finding. Apr–Jul 2021, New Zealand	Preclinical
Koçak-19 Inaktif Adjuvanlı COVID-19 vaccine Kocak Farma	Turkey	Inactivated SARS‑CoV‑2	Phase I (38) Phase 1 Study for the Determination of Safety and Immunogenicity of Different Strengths of Koçak-19 Inaktif Adjuvanlı COVID-19 Vaccine, Given Twice Intramuscularly to Healthy Volunteers, in a Placebo Controlled Study Design. Mar–Jun 2021, Turkey	Preclinical
mRNA-1283 Moderna	United States	RNA	Phase I (125) Randomized, observer-blind, dose-ranging study. Mar 2021 – Apr 2022, United States	Preclinical
DS-5670 Daiichi Sankyo	Japan	RNA	Phase I–II (152) A Phase 1/2 Study to Assess the Safety, Immunogenicity and Recommended Dose of DS-5670a (COVID-19 Vaccine) in Japanese Healthy Adults and Elderly Subjects. Mar 2021 – Jul 2022, Japan	Preclinical
CoV2-OGEN1 Syneos Health, US Specialty Formulations	United States	Subunit	Phase I (45) First-In-Human Jun–Dec 2021, New Zealand	Preclinical
KD-414 KM Biologics Co	Japan	Inactivated SARS‑CoV‑2	Phase I–II (210) Randomized, double blind, placebo control, parallel group. Mar 2021 – Dec 2022, Japan	Preclinical
CoVepiT OSE Immunotherapeutics	France	Subunit	Phase I (48) Randomized, open label. Apr–Sept 2021, France	Preclinical
ABNCoV2 Bavarian Nordic. Radboud University Nijmegen	Denmark, Netherlands	Virus-like particle	Phase I (42) Single center, sequential dose-escalation, open labelled trial. Mar–Dec 2021, Netherlands	Preclinical
HDT-301 Senai Cimatec	Brazil	RNA	Phase I (78) Randomized, open-label, dose-escalation. May–Sep 2021, Brazil	Preclinical
SC-Ad6-1 Tetherex Pharmaceuticals	United States	Viral vector	Phase I (40) First-In-Human, Open-label, Single Ascending Dose and Multidose. Jun–Dec 2021, Australia	Preclinical
Unnamed Osman ERGANIS, Scientific and Technological Research Council of Turkey	Turkey	Inactivated SARS‑CoV‑2	Phase I (50) Phase I Study Evaluating the Safety and Efficacy of the Protective Adjuvanted Inactivated Vaccine Developed Against SARS-CoV-2 in Healthy Participants, Administered as Two Injections Subcutaneously in Two Different Dosages. Apr–Oct 2021, Turkey	Preclinical
EXG-5003 Elixirgen Therapeutics, Fujita Health University	Japan, United States	RNA	Phase I–II (60) First in Human, randomized, placebo-controlled. Apr 2021 – Jan 2023, Japan	Preclinical
mRNACOVID-19 Vaccine Stemirna Therapeutics Co. Ltd.	China	RNA	Phase I (240) Randomized, double-blind, placebo-controlled. Mar–Jul 2021, China	Preclinical
IVX-411 Icosavax, Seqirus Inc.	United States	Virus-like particle	Phase I–II (168) Phase I/II (84): Randomized, observer-blinded, placebo-controlled. Jun 2021–2022, Australia	Preclinical
QazCoVac-P Research Institute for Biological Safety Problems	Kazakhstan	Subunit	Phase I–II (244) Phase I: Randomized, blind, placebo-controlled. Phase II: Randomized, open phase. Jun – Dec 2021, Kazakhstan	Preclinical
LNP-nCOV saRNA-02 MRC/UVRI & LSHTM Uganda Research Unit	Uganda	RNA	Phase I (42) A Clinical Trial to Assess the Safety and Immunogenicity of LNP-nCOV saRNA-02, a Self-amplifying Ribonucleic Acid (saRNA) Vaccine, in SARS-CoV-2 Seronegative and Seropositive Uganda Population. Sep 2021 – Jun 2022, Uganda	Preclinical
Unnamed Tsinghua University, Tianjin Medical University, Walvax Biotech	China	Viral vector	Phase I (30) May–Jun 2021, China	Preclinical
Noora Baqiyatallah University of Medical Sciences	Iran	Subunit (RBD protein recombinant vaccine)	Phase I (70) Randomized, double-blinded, placebo-controlled. Jun–Aug 2021, Iran	Preclinical
Baiya SARS-CoV-2 Vax 1 Baiya Phytopharm Co Ltd.	Thailand	Plant-based subunit (RBD-Fc + adjuvant)	Phase I (96) Randomized, open-label, dose-finding. Sep–Dec 2021, Thailand	Preclinical
CVXGA1 CyanVac LLC	United States	Viral vector	Phase I (80) Open-label July–Dec 2021, United States	Preclinical
Unnamed St. Petersburg Scientific Research Institute of Vaccines and Sera of Russia at the Federal Medical Biological Agency	Russia	Subunit (Recombinant)	Phase I–II (200) July–? 2021, Russia	Preclinical
Unnamed Shanghai Zerun Biotechnology Co., Ltd., Walvax Biotech	China	subunit (Spike protein (CHO cell) 202-CoV with CpG / alum adjuvant)	Phase I (144) Randomized, double-blinded, placebo-controlled. July–Dec 2021, China	Preclinical
Unnamed North's Academy of Medical Science Medical biology institute	North Korea	Subunit (spike protein with Angiotensin-converting enzyme 2)	Phase I–II (?) Jul 2020, North Korea	Preclinical
Unnamed Sinopharm	China	Subunit	Preclinical Awaited for the conduct on Phase I/II trials.	?
Vabiotech COVID-19 vaccine Vaccine and Biological Production Company No. 1 (Vabiotech)	Vietnam	Subunit	Preclinical Awaited for the conduct on Phase I trial.	?
INO-4802 Inovio	United States	DNA	Preclinical Awaited for the conduct on Phase I/II trials.	?
Bangavax (Bancovid) Globe Biotech Ltd. of Bangladesh	Bangladesh	RNA	Preclinical Awaiting for approval from Bangladesh government to conduct the first clinical trial.	?
Unnamed Indian Immunologicals, Griffith University	Australia, India	Attenuated	Preclinical	?
EPV-CoV-19 EpiVax	United States	Subunit (T cell epitope-based protein)	Preclinical	?
Unnamed Novavax	United States	Subunit	Preclinical	?
CV2CoV CureVac, GSK	Germany, United Kingdom	RNA	Preclinical	?
Unnamed Ministry of Health (Malaysia), Malaysia Institute of Medical Research Malaysia, Universiti Putra Malaysia	Malaysia	RNA	Preclinical	?
AdCOVID Altimmune Inc.	United States	Viral vector	Terminated (180) Double-blind, randomized, placebo-controlled, first-in-Human. Feb 2021 – Feb 2022, United States	Preclinical
LNP-nCoVsaRNA MRC clinical trials unit at Imperial College London	United Kingdom	RNA	Terminated (105) Randomized trial, with dose escalation study (15) and expanded safety study (at least 200) Jun 2020 – Jul 2021, United Kingdom	?
TMV-083 Institut Pasteur	France	Viral vector	Terminated (90) Randomized, Placebo-controlled. Aug 2020 – Jun 2021, Belgium, France	?
SARS-CoV-2 Sclamp/V451 UQ, Syneos Health, CEPI, Seqirus	Australia	Subunit (molecular clamp stabilized spike protein with MF59)	Terminated (120) Randomised, double-blind, placebo-controlled, dose-ranging. False positive HIV test found among participants. Jul–Oct 2020, Brisbane	?
V590 and V591/MV-SARS-CoV-2 Merck & Co. (Themis BIOscience), Institut Pasteur, University of Pittsburgh's Center for Vaccine Research (CVR), CEPI	United States, France	Vesicular stomatitis virus vector / Measles virus vector	Terminated In phase I, immune responses were inferior to those seen following natural infection and those reported for other SARS-CoV-2/COVID-19 vaccines.

Homologous prime-boost vaccination

In July 2021, the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) issued a joint statement reporting that a booster dose is not necessary for those who have been fully vaccinated. The statement indicates that the FDA, the CDC, and the National Institutes of Health (NIH) are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary.

Heterologous prime-boost vaccination

Some experts believe that heterologous prime-boost vaccination courses can boost immunity, and several studies have begun to examine this effect. Despite the absence of clinical data on the efficacy and safety of such heterologous combinations, Canada and several European countries have recommended a heterologous second dose for people who have received the first dose of the Oxford–AstraZeneca vaccine.

In February 2021, the Oxford Vaccine Group launched the Com-COV vaccine trial to investigate heterologous prime-boost courses of different COVID-19 vaccines. As of June 2021, the group is conducting two phase II studies: Com-COV and Com-COV2.

In Com-COV, the two heterologous combinations of the Oxford–AstraZeneca and Pfizer–BioNTech vaccines were compared with the two homologous combinations of the same vaccines, with an interval of 28 or 84 days between doses.

In Com-COV2, the first dose is the Oxford–AstraZeneca vaccine or the Pfizer vaccine, and the second dose is the Moderna vaccine, the Novavax vaccine, or a homologous vaccine equal to the first dose, with an interval of 56 or 84 days between doses.

A study in the UK is evaluating annual heterologous boosters using the following randomly selected vaccines: Oxford–AstraZeneca, Pfizer–BioNTech, Moderna, Novavax, VLA2001, CureVac, and Janssen.

Heterologous regimes in clinical trial

First dose	Second dose	Schedules	Current phase (participants), periods and locations
Oxford–AstraZeneca Pfizer–BioNTech	Oxford–AstraZeneca Pfizer–BioNTech	Days 0 and 28 Days 0 and 84	Phase II (820) Feb–Aug 2021, United Kingdom
Oxford–AstraZeneca Pfizer–BioNTech	Oxford–AstraZeneca Pfizer–BioNTech Moderna Novavax	Days 0 and 56–84	Phase II (1,050) Mar 2021 – Sep 2022, United Kingdom
Convidecia	ZF2001	Days 0 and 28 Days 0 and 56	Phase IV (120) Apr–Dec 2021, China
Oxford–AstraZeneca	Pfizer–BioNTech	Days 0 and 28	Phase II (676) Apr 2021 – Apr 2022, Spain
Oxford–AstraZeneca Pfizer–BioNTech Moderna	Pfizer–BioNTech Moderna	Days 0 and 28 Days 0 and 112	Phase II (1,200) May 2021 – Mar 2023, Canada
Pfizer–BioNTech Moderna	Pfizer–BioNTech Moderna	Days 0 and 42	Phase II (400) May 2021 – Jan 2022, France
Oxford–AstraZeneca	Pfizer–BioNTech	Days 0 and 28 Days 0 and 21–49	Phase II (3,000) May–Dec 2021, Austria
Janssen	Pfizer–BioNTech Janssen Moderna	Days 0 and 84	Phase II (432) Jun 2021 – Sep 2022, Netherlands

Efficacy

Cumulative incidence curves for symptomatic COVID‑19 infections after the first dose of the Pfizer–BioNTech vaccine (tozinameran) or placebo in a double-blind clinical trial. (red: placebo; blue: tozinameran)

Vaccine efficacy is the reduction in risk of getting the disease by vaccinated participants in a controlled trial compared with the risk of getting the disease by unvaccinated participants. An efficacy of 0% means that the vaccine does not work (identical to placebo). An efficacy of 50% means that there are half as many cases of infection as in unvaccinated individuals.

The vaccine's efficacy may be adversely effected if the arm is held improperly or squeezed so the vaccine is injected subcutaneously instead of into the muscle. The CDC guidance is to not repeat doses that are administered subcutaneously.

It is not straightforward to compare the efficacies of the different vaccines because the trials were run with different populations, geographies, and variants of the virus. In the case of COVID‑19, a vaccine efficacy of 67% may be enough to slow the pandemic, but this assumes that the vaccine confers sterilizing immunity, which is necessary to prevent transmission. Vaccine efficacy reflects disease prevention, a poor indicator of transmissibility of SARS‑CoV‑2 since asymptomatic people can be highly infectious. The US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) set a cutoff of 50% as the efficacy required to approve a COVID‑19 vaccine, with the lower limit of the 95% confidence interval being greater than 30%. Aiming for a realistic population vaccination coverage rate of 75%, and depending on the actual basic reproduction number, the necessary effectiveness of a COVID-19 vaccine is expected to need to be at least 70% to prevent an epidemic and at least 80% to extinguish it without further measures, such as social distancing.

Ranges below are 95% confidence intervals unless indicated otherwise, and all values are for all participants regardless of age, according to the references for each of the trials. By definition, the accuracy of the estimates without an associated confidence interval is unknown publicly. Efficacy against severe COVID-19 is the most important, since hospitalizations and deaths are a public health burden whose prevention is a priority. Authorized and approved vaccines have shown the following efficacies:

Vaccine	Efficacy by severity of COVID-19			Trial location	Refs
	Mild or moderate	Severe without hospitalization or death	Severe with hospitalization or death
Oxford–AstraZeneca	≈81% (60–91%)	≈100% (97.5% CI, 72–100%)	≈100%	Multinational
	≈76% (68–82%)	≈100%	≈100%	United States
Pfizer–BioNTech	≈95% (90–98%)	≈66% (−125 to 96%)		Multinational
	≈95% (90–98%)	Not reported	Not reported	United States
Janssen	≈66% (55–75%)	≈85% (54–97%)	≈100%	Multinational
	≈72% (58–82%)	≈86% (−9 to 100%)	≈100%	United States
	≈68% (49–81%)	≈88% (8–100%)	≈100%	Brazil
	≈64% (41–79%)	≈82% (46–95%)	≈100%	South Africa
Moderna	≈94% (89–97%)	≈100%	≈100%	United States
BBIBP-CorV	≈78% (65–86%)	≈100%	≈100%	Multinational
Sputnik V	≈92% (86–95%)	≈100% (94–100%)	≈100%	Russia
CoronaVac	≈51% (36–62%)	≈84% (58–94%)	≈100% (56–100%)	Brazil
	≈84% (65–92%)	≈100%	≈100% (20–100%)	Turkey
Covaxin	≈78% (65–86%)	≈93% (57–100%)		India
Sputnik Light	≈79%	Not reported	Not reported	Russia
Convidecia	≈66%	≈91%	Not reported	Multinational
WIBP-CorV	≈73% (58–82%)	≈100%	≈100%	Multinational
Abdala	≈92% (86–96%)	Not reported	Not reported	Cuba
Soberana 02	≈62%	Not reported	Not reported	Cuba
Novavax	≈89% (75–95%)	≈100%	≈100%	United Kingdom
	≈60% (20–80%)	≈100%	≈100%	South Africa
	≈90%	Not reported	Not reported	United States
		Not reported	Not reported	Mexico
CureVac	≈48%	Not reported	Not reported	Multinational
ZyCoV-D	≈67%	Not reported	Not reported	India

Effectiveness

The real-world studies of vaccine effectiveness measure to which extent a certain vaccine has succeeded in preventing COVID-19 infection, symptoms, hospitalization and death for the vaccinated individuals in a large population under routine conditions that are less than ideal.

• In Israel, among the 715,425 individuals vaccinated by the Moderna or Pfizer-BioNTech vaccines during the period 20 December 2020, to 28 January 2021, it was observed for the period starting seven days after the second shot, that only 317 people (0.04%) became sick with mild/moderate Covid-19 symptoms and only 16 people (0.002%) were hospitalized.
• The Pfizer-BioNTech and Moderna Covid-19 vaccines provide highly effective protection, according to a report from the US Centers for Disease Control and Prevention (CDC). Under real-world conditions, mRNA vaccine effectiveness of full immunization (≥14 days after second dose) was 90% against SARS-CoV-2 infections regardless of symptom status; vaccine effectiveness of partial immunization (≥14 days after first dose but before second dose) was 80%.
• 15,121 health care workers from 104 hospitals in England, that all had tested negative for COVID-19 antibodies prior of the study, were followed by RT-PCR tests twice a week from 7 December 2020 to 5 February 2021, during a time when the Alpha variant (lineage B.1.1.7) was in circulation as the dominant variant. The study compared the positive results for the 90.7% vaccinated share of their cohort with the 9.3% unvaccinated share, and found that the Pfizer-BioNTech vaccine reduced all infections (including asymptomatic), by 72% (58-86%) three weeks after the first dose and 86% (76-97%) one week after the second dose.
• A study of the general population in Israel conducted from 17 January to 6 March 2021, during a time when the Alpha variant was in circulation as the dominant variant, found that the Pfizer vaccine reduced asymptomatic COVID-19 infections by 94% and symptomatic COVID-19 infections by 97%.
• A study, among pre-surgical patients across the Mayo Clinic system in the United States, showed that mRNA vaccines were 80% protective against asymptomatic infections.
• A study in England found that a single dose of the Oxford–AstraZeneca COVID-19 vaccine is about 73% (27–90%) effective in people aged 70 and older.

Vaccine	Effectiveness by severity of COVID-19				Study location	Refs
	Asymptomatic	Symptomatic	Hospitalization	Death
Oxford–AstraZeneca	Not reported	≈89% (78–94%)	Not reported		England
	Not reported			≈89%	Argentina
Pfizer–BioNTech	≈92% (91–92%)	≈97% (97–97%)	≈98% (97–98%)	≈97% (96–97%)	Israel
	≈92% (88–95%)	≈94% (87–98%)	≈87% (55–100%)	≈97%	Israel
	Not reported	≈78% (77–79%)	≈98% (96–99%)	≈96% (95–97%)	Uruguay
	≈85% (74–96%)		Not reported		England
	≈90% (68–97%)		Not reported	≈100%	United States
Moderna	≈90% (68–97%)		Not reported	≈100%	United States
BBIBP-CorV	Not reported			≈84%	Argentina
	Not reported			≈94%	Peru
Sputnik V	Not reported	≈98%	Not reported		Russia
	Not reported	≈98%	≈100%	≈100%	United Arab Emirates
	Not reported			≈93%	Argentina
CoronaVac	Not reported	≈66% (65–67%)	≈88% (87–88%)	≈86% (85–88%)	Chile
	Not reported	≈60% (59–61%)	≈91% (89–93%)	≈95% (93–96%)	Uruguay
	Not reported	≈94%	≈96%	≈98%	Indonesia
	Not reported	≈80%	≈86%	≈95%	Brazil
Sputnik Light	Not reported	≈79%	≈88%	≈85%	Argentina

Critical coverage

See also: Herd immunity § Vaccination, and COVID-19 § Immunity

While the most immediate goal of vaccination during a pandemic is to protect individuals from severe disease, a long-term goal is to eventually eradicate it. To do so, the proportion of the population that must be immunized must be greater than the critical vaccination coverage $V_{c}$. This value can be calculated from the basic reproduction number $R_{0}$ and the vaccine effectiveness against transmission $E$ as:

$V_{c}={\frac {1-1/R_{0}}{E}}$

Assuming R₀ ≈ 2.87 for SARS-CoV-2, then, for example, the coverage level would have to be greater than 72.4% for a vaccine that is 90% effective against transmission. Using the same relationship, the required effectiveness against transmission can be calculated as:

$E={\frac {1-1/R_{0}}{V_{c}}}$

Assuming the same R₀ ≈ 2.87, the effectiveness against transmission would have to be greater than 86.9% for a realistic coverage level of 75% or 65.2% for an impossible coverage level of 100%. Less effective vaccines would not be able to eradicate the disease.

Several post-marketing studies have already estimated the effectiveness of some vaccines against asymptomatic infection. Prevention of infection has an impact on slowing transmission (particularly asymptomatic and pre-symptomatic), but the exact extent of this effect is still under investigation.

Some variants of SARS-CoV-2 are more transmissible, showing an increased effective reproduction number, indicating an increased basic reproduction number. Controlling them requires greater vaccine coverage, greater vaccine effectiveness against transmission, or a combination of both.

Variants

Play media

World Health Organization video describing how variants proliferate in unvaccinated areas.

See also: Variants of SARS-CoV-2

The interplay between the SARS-CoV-2 virus and its human hosts was initially natural but is now being altered by the prompt availability of vaccines. The potential emergence of a SARS-CoV-2 variant that is moderately or fully resistant to the antibody response elicited by the COVID-19 vaccines may necessitate modification of the vaccines. Trials indicate many vaccines developed for the initial strain have lower efficacy for some variants against symptomatic COVID-19. As of February 2021, the US Food and Drug Administration believed that all FDA authorized vaccines remained effective in protecting against circulating strains of SARS-CoV-2.

Alpha (lineage B.1.1.7)

Main article: SARS-CoV-2 Alpha variant

Limited evidence from various preliminary studies reviewed by the WHO has indicated retained efficacy/effectiveness against disease from Alpha with the Oxford–AstraZeneca vaccine, Pfizer–BioNTech and Novavax, with no data for other vaccines yet. Relevant to how vaccines can end the pandemic by preventing asymptomatic infection, they have also indicated retained antibody neutralization against Alpha with most of the widely distributed vaccines (Sputnik V, Pfizer–BioNTech, Moderna, CoronaVac, BBIBP-CorV, Covaxin), minimal to moderate reduction with the Oxford–AstraZeneca and no data for other vaccines yet.

In December 2020, a new SARS‑CoV‑2 variant, the Alpha variant or lineage B.1.1.7, was identified in the UK.

Early results suggest protection to the variant from the Pfizer-BioNTech and Moderna vaccines.

One study indicated that the Oxford–AstraZeneca COVID-19 vaccine had an efficacy of 42–89% against Alpha, versus 71–91% against other variants.

Preliminary data from a clinical trial indicates that the Novavax vaccine is ~96% effective for symptoms against the original variant and ~86% against Alpha.

Beta (lineage B.1.351)

Main article: SARS-CoV-2 Beta variant

Limited evidence from various preliminary studies reviewed by the WHO have indicated reduced efficacy/effectiveness against disease from Beta with the Oxford–AstraZeneca vaccine (possibly substantial), Novavax (moderate), Pfizer–BioNTech and Janssen (minimal), with no data for other vaccines yet. Relevant to how vaccines can end the pandemic by preventing asymptomatic infection, they have also indicated possibly reduced antibody neutralization against Beta with most of the widely distributed vaccines (Oxford–AstraZeneca, Sputnik V, Janssen, Pfizer–BioNTech, Moderna, Novavax; minimal to substantial reduction) except CoronaVac and BBIBP-CorV (minimal to modest reduction), with no data for other vaccines yet.

Moderna has launched a trial of a vaccine to tackle the Beta variant or lineage B.1.351. On 17 February 2021, Pfizer announced neutralization activity was reduced by two-thirds for this variant, while stating that no claims about the efficacy of the vaccine in preventing illness for this variant could yet be made. Decreased neutralizing activity of sera from patients vaccinated with the Moderna and Pfizer-BioNTech vaccines against Beta was later confirmed by several studies. On 1 April 2021, an update on a Pfizer/BioNTech South African vaccine trial stated that the vaccine was 100% effective so far (i.e., vaccinated participants saw no cases), with six of nine infections in the placebo control group being the Beta variant.

In January 2021, Johnson & Johnson, which held trials for its Janssen vaccine in South Africa, reported the level of protection against moderate to severe COVID-19 infection was 72% in the United States and 57% in South Africa.

On 6 February 2021, the Financial Times reported that provisional trial data from a study undertaken by South Africa's University of the Witwatersrand in conjunction with Oxford University demonstrated reduced efficacy of the Oxford–AstraZeneca COVID-19 vaccine against the variant. The study found that in a sample size of 2,000 the AZD1222 vaccine afforded only "minimal protection" in all but the most severe cases of COVID-19. On 7 February 2021, the Minister for Health for South Africa suspended the planned deployment of about a million doses of the vaccine whilst they examine the data and await advice on how to proceed.

In March 2021, it was reported that the "preliminary efficacy" of the Novavax vaccine (NVX-CoV2373) against Beta for mild, moderate, or severe COVID-19 for HIV-negative participants is 51%.

Gamma (lineage P.1)

Main article: SARS-CoV-2 Gamma variant

Limited evidence from various preliminary studies reviewed by the WHO have indicated likely retained efficacy/effectiveness against disease from Gamma with CoronaVac and BBIBP-CorV, with no data for other vaccines yet. Relevant to how vaccines can end the pandemic by preventing asymptomatic infection, they have also indicated retained antibody neutralization against Gamma with Oxford–AstraZeneca and CoronaVac (no to minimal reduction) and slightly reduced neutralization with Pfizer–BioNTech and Moderna (minimal to moderate reduction), with no data for other vaccines yet.

The Gamma variant or lineage P.1 variant (also known as 20J/501Y.V3), initially identified in Brazil, seems to partially escape vaccination with the Pfizer-BioNTech vaccine.

Delta (lineage B.1.617)

Main article: SARS-CoV-2 Delta variant

Limited evidence from various preliminary studies reviewed by the WHO have indicated likely retained efficacy/effectiveness against disease from Delta with the Oxford–AstraZeneca vaccine and Pfizer–BioNTech, with no data for other vaccines yet. Relevant to how vaccines can end the pandemic by preventing asymptomatic infection, they have also indicated reduced antibody neutralization against Delta with single-dose Oxford–AstraZeneca (substantial reduction), Pfizer–BioNTech and Covaxin (modest to moderate reduction), with no data for other vaccines yet.

In October 2020, a new variant was discovered in India, which was named lineage B.1.617. There were very few detections until January 2021, but by April it had spread to at least 20 countries in all continents except Antarctica and South America. Among some 15 defining mutations, it has spike mutations D111D (synonymous), G142D, P681R, E484Q and L452R, the latter two of which may cause it to easily avoid antibodies. The variant has frequently been referred to as a 'Double mutant', even though in this respect it is not unusual. In an update on 15 April 2021, PHE designated lineage B.1.617 as a 'Variant under investigation', VUI-21APR-01. On 6 May 2021, Public Health England escalated lineage B.1.617.2 from a Variant Under Investigation to a Variant of Concern based on an assessment of transmissibility being at least equivalent to the Alpha variant.

Effect of neutralizing antibodies

One study found that the in vitro concentration (titer) of neutralizing antibodies elicited by a COVID-19 vaccine is a strong correlate of immune protection. The relationship between protection and neutralizing activity is nonlinear. A neutralization as low as 3% (95% CI, 1–13%) of the level of convalescence results in 50% efficacy against severe disease, with 20% (14–28%) resulting in 50% efficacy against detectable infection. Protection against infection quickly decays, leaving individuals susceptible to mild infections, while protection against severe disease is largely retained and much more durable. The observed half-life of neutralizing titers was 65 days for mRNA vaccines (Pfizer–BioNTech, Moderna) during the first 4 months, increasing to 108 days over 8 months. Greater initial efficacy against infection likely results in a higher level of protection against serious disease in the long term (beyond 10 years, as seen in other vaccines such as smallpox, measles, mumps, and rubella), although the authors acknowledge that their simulations only consider protection from neutralizing antibodies and ignore other immune protection mechanisms, such as cell-mediated immunity, which may be more durable. This observation also applies to efficacy against variants and is particularly significant for vaccines with a lower initial efficacy; for example, a 5-fold reduction in neutralization would indicate a reduction in initial efficacy from 95% to 77% against a specific variant, and from a lower efficacy of 70% to 32% against that variant. For the Oxford–AstraZeneca vaccine, the observed efficacy is below the predicted 95% confidence interval. It is higher for Sputnik V and the convalescent response, and is within the predicted interval for the other vaccines evaluated (Pfizer–BioNTech, Moderna, Janssen, CoronaVac, Covaxin, Novavax).

Side effects

Serious adverse events associated with receipt of new vaccines targeting COVID-19 are of high interest to the public. All vaccines that are administered via intramuscular injection, including COVID-19 vaccines, have side effects related to the mild trauma associated with the procedure and introduction of a foreign substance into the body. These include soreness, redness, rash, and inflammation at the injection site. Other common side effects include fatigue, headache, myalgia (muscle pain), and arthralgia (joint pain) which generally resolve within a few days. One less-frequent side effect (that generally occurs in less than 1 in 1,000 people) is hypersensitivity (allergy) to one or more of the vaccine's ingredients, which in some rare cases may cause anaphylaxis.

Specific rare side effects

More serious side effects are very rare because a vaccine would not be approved even for emergency use if it had any known frequent serious adverse effects. For example, the Janssen COVID-19 vaccine reported rare Formation of blood clots in the blood vessels in combination with low levels of blood platelets known as thrombosis with thrombocytopenia syndrome (TTS) which occurred at a rate of about 7 per 1 million vaccinated women ages 18–49 years old; and even more rarely for other populations. The Pfizer–BioNTech vaccine has seen very rare cases of myocarditis and pericarditis reported in the United States in about 13 per 1 million young people (mostly in males and mostly over the age of 16) after vaccination with the Pfizer–BioNTech or the Moderna vaccine. Recoverly from this rare side effect is quick with most individuals with adequate treatment and rest.

Society and culture

Distribution

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COVID-19 vaccine distribution by location

Location		Vaccinated	%
	World	2,167,146,974	27%
	China	1,601,249,000
	European Union	259,314,422	58%
	India	352,545,271	25%
	United States	189,494,180	56%
	Brazil	102,294,772	48%
	Germany	51,007,130	60%
	United Kingdom	46,689,242	68%
	Japan	48,270,230	38%
	Turkey	40,330,955	47%
	France	39,901,727	59%
	Italy	37,864,407	62%
	Indonesia	45,734,912	16%
	Mexico	44,188,943	34%
	Russia	35,565,564	24%
	Spain	31,315,140	66%
	Canada	26,878,305	71%
	Poland	18,192,439	48%
	Argentina	24,302,432	53%
	Pakistan	26,248,235
	Saudi Arabia	18,451,457	53%
	Colombia	16,455,361	32%
	Chile	13,772,232	72%
	South Korea	18,382,137	35%
	Morocco	12,971,479	35%
	Netherlands	11,855,109	69%
	Malaysia	12,841,212	39%
	Philippines	11,204,316	10%
	United Arab Emirates	7,734,137	78%
	Thailand	12,307,788	17%
	Belgium	7,938,784	68%
	Peru	7,819,321	23%
	Portugal	6,918,605	67%
	Cambodia	7,043,969	42%
	Australia	8,048,704	31%
	Israel	5,775,845	66%
	Bangladesh	6,622,525	4%
	Sweden	6,330,448	62%
	Greece	5,635,856	54%
	Czechia	5,586,127	52%
	Iran	7,741,936	9%
	Sri Lanka	8,232,194	38%
	Ecuador	7,960,999	45%
	Dominican Republic	5,491,708	50%
	Austria	5,264,597	58%
	Romania	4,954,809	25%
	Cuba	3,496,617	30%
	Switzerland	4,631,104	53%
	Kazakhstan	5,230,750	27%
	Taiwan	7,273,091	30%
	Singapore	4,267,577	72%
	Denmark	4,146,424	71%
	South Africa	5,580,927	9%
	Uzbekistan	3,667,979	10%
	Ireland	3,248,996	65%
	Hungary	5,611,260	58%
	Serbia	2,821,702	41%
	Hong Kong	3,132,660	41%
	Finland	3,648,321	65%
	Egypt	3,697,974	3%
	Vietnam	4,825,209	4%
	Ukraine	3,350,500	7%
	Norway	3,433,640	63%
	Nepal	3,544,043	12%
	Jordan	2,878,541	28%
	Uruguay	2,553,268	73%
	Azerbaijan	2,731,114	26%
	Bolivia	2,834,736	24%
	Slovakia	2,248,646	41%
	El Salvador	2,710,883	41%
	Mongolia	2,161,612	65%
	Qatar	2,028,988	70%
	Costa Rica	2,352,430	46%
	Croatia	1,628,084	39%
	Tunisia	1,699,805	14%
	Lithuania	1,385,066	50%
	Bahrain	1,105,717	64%
	Panama	1,567,945	36%
	Ethiopia	2,197,813	1%
	Belarus	1,334,540	14%
	Zimbabwe	1,491,493	10%
	Paraguay	1,837,008	25%
	Bulgaria	1,017,204	14%
	Lebanon	1,098,232	16%
	Laos	1,062,365	14%
	Oman	1,550,910	30%
	Guatemala	1,561,791	8%
	New Zealand	1,059,685	21%
	Slovenia	909,574	43%
	Honduras	1,511,974	15%
	Kenya	1,049,847	1%
	Angola	958,373	2%
	Latvia	758,216	40%
	Afghanistan	939,835	2%
	Ghana	865,422	2%
	Mauritius	634,013	49%
	Albania	640,047	22%
	Uganda	1,135,036	2%
	Estonia	630,404	47%
	Moldova	538,869	13%
	Palestine	582,721	11%
	Cyprus	528,889	59%
	Ivory Coast	943,437	3%
	Senegal	640,013	3%
	North Macedonia	500,995	24%
	Sudan	627,833	1%
	Guinea	513,637	3%
	Malta	396,087	89%
	Luxembourg	392,073	62%
	Mozambique	372,085	1%
	Bosnia and Herzegovina	381,381	11%
	Maldives	321,429	59%
	Trinidad and Tobago	365,597	26%
	Libya	546,745	7%
	Fiji	441,171	49%
	Kyrgyzstan	403,640	6%
	Macao	280,803	43%
	Tajikistan	462,542	4%
	Bhutan	486,242	63%
	Iceland	267,830	78%
	Togo	304,278	3%
	Malawi	390,738	2%
	Georgia	288,573	7%
	Rwanda	423,182	3%
	Nicaragua	252,766	3%
	Zambia	282,556	1%
	Kosovo	263,847	13%
	Guyana	248,970	31%
	Timor-Leste	276,510	20%
	Cameroon	279,987	1%
	Botswana	209,890	8%
	Montenegro	171,423	27%
	Yemen	298,161	1%
	Equatorial Guinea	178,913	12%
	Jamaica	178,728	6%
	Suriname	185,653	31%
	Namibia	154,350	6%
	Northern Cyprus	108,923	28%
	Mauritania	177,259	3%
	Curaçao	92,386	56%
	Barbados	99,154	34%
	Belize	121,487	30%
	Congo	163,742	2%
	Cabo Verde	141,276	25%
	French Polynesia	83,210	29%
	Armenia	108,674	3%
	Brunei	126,050	28%
	Seychelles	72,882	74%
	Jersey	73,568	72%
	Aruba	72,598	68%
	Comoros	84,740	9%
	New Caledonia	66,159	23%
	Isle of Man	64,871	76%
	Bahamas	60,578	15%
	Cayman Islands	49,672	75%
	Central African Republic	85,381	1%
	Guernsey	92,011
	Papua New Guinea	78,399	0%
	Gabon	52,830	2%
	Bermuda	41,651	66%
	Andorra	48,445	62%
	Democratic Republic of the Congo	78,871	0%
	Samoa	60,044	30%
	Gibraltar	39,329	116%
	Lesotho	36,637	1%
	Antigua and Barbuda	37,841	38%
	Eswatini	38,326	3%
	Faroe Islands	34,657	70%
	Greenland	35,434	62%
	Benin	43,377	0%
	South Sudan	52,226	0%
	Saint Lucia	32,068	17%
	Turks and Caicos Islands	24,567	63%
	San Marino	22,907	67%
	Solomon Islands	35,167	5%
	Sint Maarten	23,885	55%
	Sao Tome and Principe	32,090	14%
	Gambia	31,254	1%
	Saint Kitts and Nevis	23,755	44%
	Turkmenistan	32,240	0%
	Monaco	21,796	55%
	Dominica	20,784	28%
	Tonga	28,753	27%
	Liechtenstein	20,632	54%
	Burkina Faso	34,749	0%
	Grenada	21,014	18%
	Chad	21,581	0%
	British Virgin Islands	15,620	51%
	Saint Vincent and the Grenadines	15,711	14%
	Guinea-Bissau	24,000	1%
	Vanuatu	23,881	7%
	Cook Islands	10,931	62%
	Anguilla	9,398	62%
	Nauru	7,533	69%
	Wallis and Futuna	4,629	41%
	St. Helena, Ascension, Tristan	4,361	71%
	Caribbean Netherlands	5,726	21%
	Tuvalu	4,772	40%
	Falkland Islands	2,632	75%
	Haiti	4,078	0%
	Montserrat	1,439	28%
	Niue	1,184	73%
	Pitcairn	47	100%

These paragraphs are an excerpt from Deployment of COVID-19 vaccines[edit]

As of 28 July 2021, 4.01 billion COVID-19 vaccine doses had been administered worldwide based on official reports from national health agencies collated by Our World in Data.

During a pandemic on the rapid timeline and scale of COVID-19 cases in 2020, international organizations like the World Health Organization (WHO) and Coalition for Epidemic Preparedness Innovations (CEPI), vaccine developers, governments, and industry are evaluating the distribution of the eventual vaccine(s). Individual countries producing a vaccine may be persuaded to favor the highest bidder for manufacturing or provide first-service to their own country. Experts emphasize that licensed vaccines should be available and affordable for people at the frontline of healthcare and having the greatest need. In April 2020, it was reported that the UK agreed to work with 20 other countries and global organizations including France, Germany and Italy to find a vaccine and to share the results and that UK citizens would not get preferential access to any new COVID‑19 vaccines developed by taxpayer-funded UK universities. Several companies plan to initially manufacture a vaccine at artificially low pricing, then increase prices for profitability later if annual vaccinations are needed and as countries build stock for future needs.

An April 2020 CEPI report stated: "Strong international coordination and cooperation between vaccine developers, regulators, policymakers, funders, public health bodies, and governments will be needed to ensure that promising late-stage vaccine candidates can be manufactured in sufficient quantities and equitably supplied to all affected areas, particularly low-resource regions." The WHO and CEPI are developing financial resources and guidelines for global deployment of several safe, effective COVID‑19 vaccines, recognizing the need is different across countries and population segments. For example, successful COVID‑19 vaccines would likely be allocated first to healthcare personnel and populations at greatest risk of severe illness and death from COVID‑19 infection, such as the elderly or densely-populated impoverished people.

A map of COVID-19 vaccination rates in the USA by state, as of 21 July 2021.

Access

Main article: Deployment of COVID-19 vaccines § Equitable access

Nations pledged to buy doses of COVID‑19 vaccine before the doses were available. Though high-income nations represent only 14% of the global population, as of 15 November 2020, they had contracted to buy 51% of all pre-sold doses. Some high-income nations bought more doses than would be necessary to vaccinate their entire populations.

Elderly receiving second dose of CoronaVac vaccine in Brazil.

On 18 January 2021, WHO Director-General Tedros Adhanom Ghebreyesus warned of problems with equitable distribution: "More than 39 million doses of vaccine have now been administered in at least 49 higher-income countries. Just 25 doses have been given in one lowest-income country. Not 25 million; not 25 thousand; just 25."

Production of Sputnik V vaccine in Brazil

In March, it was revealed the US attempted to convince Brazil not to purchase the Sputnik V COVID-19 vaccine, fearing "Russian influence" in Latin America. Some nations involved in long-standing territorial disputes have reportedly had their access to vaccines blocked by competing nations; Palestine has accused Israel blocking vaccine delivery to Gaza, while Taiwan has suggested that China has hampered its efforts to procure vaccine doses.

A single dose of the COVID‑19 vaccine by AstraZeneca would cost 47 Egyptian pounds (EGP) and the authorities are selling it between 100 and 200 EGP. A report by Carnegie Endowment for International Peace cited the poverty rate in Egypt as around 29.7 percent, which constitutes approximately 30.5 million people, and claimed that about 15 million of the Egyptians would be unable to gain access to the luxury of vaccination. A human rights lawyer, Khaled Ali launched a lawsuit against the government, forcing them to provide vaccination free of cost to all members of the public.

According to immunologist Dr. Anthony Fauci, mutant strains of virus and limited vaccine distribution pose continuing risks and he said: "we have to get the entire world vaccinated, not just our own country." Edward Bergmark and Arick Wierson are calling for an global vaccination effort and wrote that the wealthier nations' "me-first" mentality could ultimately backfire, because the spread of the virus in poorer countries would lead to more variants, against which the vaccines could be less effective.

On 10 March 2021, the United States, Britain, European Union nations and other WTO members, blocked a push by more than eighty developing countries to waive COVID‑19 vaccine patent rights in an effort to boost production of vaccines for poor nations. On 5 May 2021, the Biden administration announced that it supports waiving intellectual property protections for COVID-19 vaccines. The Members of the European Parliament have backed a motion demanding the temporary lifting of intellectual properties rights for COVID‑19 vaccines. Commission vice-president Valdis Dombrovskis, stressed that while the EU is ready to discuss the issue of patent waivers, its proposed solutions include limiting export restrictions, resolving production bottlenecks, looking into compulsory licensing, investing in manufacturing capacity in developing countries and increasing contributions to the COVAX scheme.

In a meeting in April 2021, the World Health Organization's emergency committee addressed concerns of persistent inequity in the global vaccine distribution. Although 9 percent of the world's population lives in the 29 poorest countries, these countries had received only 0.3% of all vaccines administered as of May 2021. Locally, in a Agência Pública article from March 15, 2021, Brazil vaccinated twice more white than black people and noticed the fact that the mortality of COVID-19 is bigger in the black population.

In May 2021, UNICEF made an urgent appeal to industrialised nations to pool their excess COVID-19 vaccine capacity to make up for a 125-million-dose gap in the COVAX program. The program mostly relied on the Oxford–AstraZeneca COVID-19 vaccine produced by SRI, which faced serious supply problems due to increased domestic vaccine needs in India from March to June 2021. Only a limited amount of vaccines can be distributed efficiently, and the shortfall of vaccines in South America and parts of Asia are due to a lack of expedient donations by richer nations. International aid organisations have pointed at Nepal, Sri Lanka, and Maldives as well as Argentina and Brazil, and some parts of the Caribbean as problem areas, where vaccines are in short supply. UNICEF has also been critical towards proposed donations of Moderna and Pfizer vaccines since these are not slated for delivery until the second half of 2021, or early 2022.

On July 1, 2021, the heads of the World Bank Group, International Monetary Fund, World Health Organization and World Trade Organization said in a joint statement: "As many countries are struggling with new variants and a third wave of COVID-19 infections, accelerating access to vaccines becomes even more critical to ending the pandemic everywhere and achieving broad-based growth. We are deeply concerned about the limited vaccines, therapeutics, diagnostics, and support for deliveries available to developing countries."

Preventive measures after vaccination

While vaccines substantially reduce the probability of infection, it is still possible for fully vaccinated people to contract and spread COVID-19. Public health agencies have recommended that vaccinated people continue using preventive measures (wear face masks, social distance, wash hands) to avoid infecting others, especially vulnerable people, particularly in areas with high community spread. Governments have indicated that such recommendations will be reduced as vaccination rates increase and community spread declines.

Inside of a vaccination center in Brussels, Belgium

Liability

There are liability shields in place to protect pharmaceutical companies like Pfizer and Moderna from negligence claims related to COVID-19 vaccines (and treatments). These liability shields took effect on 4 February 2020, when the US Secretary of Health and Human Services Alex Azar published a notice of declaration under the Public Readiness and Emergency Preparedness Act (PREP Act) for medical countermeasures against COVID‑19, covering "any vaccine, used to treat, diagnose, cure, prevent, or mitigate COVID‑19, or the transmission of SARS-CoV-2 or a virus mutating therefrom". The declaration precludes "liability claims alleging negligence by a manufacturer in creating a vaccine, or negligence by a health care provider in prescribing the wrong dose, absent willful misconduct". In other words, absent "willful misconduct", these companies can not be sued for money damages for any injuries that occur between 2020 and 2024 from the administration of vaccines and treatments related to COVID-19. The declaration is effective in the United States through 1 October 2024.

In December 2020, the UK government granted Pfizer legal indemnity for its COVID-19 vaccine.

In the European Union, the COVID‑19 vaccines are licensed under a Conditional Marketing Authorisation which does not exempt manufacturers from civil and administrative liability claims. While the purchasing contracts with vaccine manufacturers remain secret, they do not contain liability exemptions even for side-effects not known at the time of licensure.

The Bureau of Investigative Journalism, a nonprofit news organization, reported in an investigation that unnamed officials in some countries, such as Argentina and Brazil, said that Pfizer demanded guarantees against costs of legal cases due to adverse effects in the form of liability waivers and sovereign assets such as federal bank reserves, embassy buildings or military bases, going beyond the expected from other countries such as the US. During the pandemic parliamentary inquiry in Brazil, Pfizer's representative said that its terms for Brazil are the same as for all other countries with which it has signed deals.

Misinformation

Main article: COVID‑19 misinformation § Vaccines

Anti-vaccination activists and other people spread a variety of rumors, including overblown claims about side effects, a story about COVID-19 being spread by childhood vaccines, misrepresentations about how the immune system works, and when and how COVID-19 vaccines are made.

Fake vaccines containing salt water have also been administered in some countries.

Vaccine hesitancy

Main article: Vaccine hesitancy

Estimates from two surveys were that 67% or 80% of people in the U.S. would accept a new vaccination against COVID‑19, with wide disparity by education level, employment status, ethnicity, and geography. In March 2021, 19% of US adults claimed to have been vaccinated while 50% announced plans to get vaccinated.

Encouragement by public figures and celebrities

Many public figures and celebrities have publicly declared that they have been vaccinated against COVID‑19, and encouraged people to get vaccinated. Many have made video recordings or otherwise documented their vaccination. They do this partly to counteract vaccine hesitancy and COVID‑19 vaccine conspiracy theories.

Politicians and heads of state

Peru's interim President Francisco Sagasti gets vaccinated against COVID-19 at a military hospital in Lima

Several current and former heads of state and government ministers have released photographs of their vaccinations, encouraging others to be vaccinated, including Kyriakos Mitsotakis, Zdravko Marić, Olivier Véran, Joe Biden, Barack Obama, George W. Bush, Bill Clinton, the Dalai Lama, Narendra Modi, Justin Trudeau, Alexandria Ocasio-Cortez, Nancy Pelosi and Kamala Harris.

Elizabeth II and Prince Philip announced they had the vaccine, breaking from protocol of keeping the British royal family's health private. Pope Francis and Pope Emeritus Benedict both announced they had been vaccinated.

Musicians

Dolly Parton recorded herself getting vaccinated with the Moderna vaccine she helped fund, she encouraged people to get vaccinated and created a new version of her song "Jolene" called "Vaccine". Patti Smith, Yo-Yo Ma, Carole King, Tony Bennett, Mavis Staples, Brian Wilson, Joel Grey, Loretta Lynn, Willie Nelson, and Paul Stanley have all released photographs of them being vaccinated and encouraged others to do so. Grey stated "I got the vaccine because I want to be safe. We've lost so many people to COVID. I've lost a few friends. It's heartbreaking. Frightening."

Actresses and actors

Amy Schumer, Rosario Dawson, Arsenio Hall, Danny Trejo, Mandy Patinkin, Samuel L. Jackson, Arnold Schwarzenegger, Sharon Stone, Kate Mulgrew, Jeff Goldblum, Jane Fonda, Anthony Hopkins, Bette Midler, Kim Cattrall, Isabella Rossellini, Christie Brinkley, Cameran Eubanks, Hugh Bonneville, Alan Alda, David Harbour, Sean Penn, Amanda Kloots, Ian McKellen and Patrick Stewart have released photographs of themselves getting vaccinated and encouraging others to do the same. Dame Judi Dench and Joan Collins announced they have been vaccinated.

TV personalities

Martha Stewart, Jonathan Van Ness, Al Roker and Dan Rather released photographs of themselves getting vaccinated and encouraged others to do the same. Stephen Fry also shared a photograph of being vaccinated; he wrote, "It's a wonderful moment, but you feel that it's not only helpful for your own health, but you know that you're likely to be less contagious if you yourself happen to carry it ... It's a symbol of being part of society, part of the group that we all want to protect each other and get this thing over and done with." Sir David Attenborough announced that he has been vaccinated. Dutch TV personality Beau van Erven Dorens got his vaccination on live TV in his late-night talkshow on 3 June 2021.

Athletes

Magic Johnson and Kareem Abdul-Jabbar released photographs of themselves getting vaccinated and encouraged others to do the same; Abdul-Jabbar said, "We have to find new ways to keep each other safe."

Specific communities

Romesh Ranganathan, Meera Syal, Adil Ray, Sadiq Khan and others produced a video specifically encouraging ethnic minority communities in the UK to be vaccinated including addressing conspiracy theories stating "there is no scientific evidence to suggest it will work differently on people from ethnic minorities and that it does not include pork or any material of fetal or animal origin."

Oprah Winfrey and Whoopi Goldberg have spoken about being vaccinated and encouraged other black Americans to be so. Stephanie Elam volunteered to be a trial volunteer stating "a large part of the reason why I wanted to volunteer for this COVID‑19 vaccine research – more Black people and more people of color need to be part of these trials so more diverse populations can reap the benefits of this medical research."

Research

A study is investigating the long-lasting protection against SARS-CoV-2 provided by the mRNA vaccines.

See also

• 2009 swine flu pandemic vaccine
• COVID-19 drug development
• COVID-19 drug repurposing research

Further reading

• Krause PR, Fleming TR, Longini IM, Peto R, Briand S, Heymann DL, et al. (July 2021). "SARS-CoV-2 Variants and Vaccines". N Engl J Med. 385 (2): 179–86. doi:10.1056/NEJMsr2105280. PMC 8262623. PMID 34161052.
• Kyriakidis NC, López-Cortés A, González EV, Grimaldos AB, Prado EO (February 2021). "SARS-CoV-2 vaccines strategies: a comprehensive review of phase 3 candidates". NPJ Vaccines. 6 (1): 28. doi:10.1038/s41541-021-00292-w. PMC 7900244. PMID 33619260.
• Ramsay M, ed. (2020). "Chapter 14a: COVID-19". Immunisation against infectious disease. Public Health England.
• Development and Licensure of Vaccines to Prevent COVID-19: Guidance for Industry (PDF) (Report). U.S. Food and Drug Administration (FDA). June 2020. Lay summary.

Vaccine protocols

• "Protocol mRNA-1273-P301" (PDF). Moderna.
• "Protocol C4591001 PF-07302048 (BNT162 RNA-Based COVID-19 Vaccines)" (PDF). Pfizer.
• "Protocol AZD1222 – D8110C00001" (PDF). AstraZeneca.
• "Protocol VAC31518COV3001; Phase 3 (ENSEMBLE)" (PDF). Janssen Vaccines & Prevention.
• "Protocol VAC31518COV3009; Phase 3 (ENSEMBLE 2)" (PDF). Janssen Vaccines & Prevention.

External links

• "The COVID-19 candidate vaccine landscape". World Health Organization (WHO).
• COVID‑19 Vaccine Tracker. Regulatory Affairs Professionals Society (RAPS)
• "STAT's Covid-19 Drugs and Vaccines Tracker". Stat.
• "COVID-19 vaccines: development, evaluation, approval and monitoring". European Medicines Agency (EMA).
• "Vaccine Development – 101". U.S. Food and Drug Administration (FDA).
• "Coronavirus Variants and Mutations". The New York Times.
• M.I.T. Lecture 10: Kizzmekia Corbett, Vaccines" on YouTube
• "COVID-19 vaccines: research and development". European Medicines Agency (EMA).
• "The 5 Stages of COVID-19 Vaccine Development: What You Need to Know About How a Clinical Trial Works". Johnson & Johnson.
• "How patent laws get in the way of the global coronavirus vaccine rollout". The Conversation.
• "A New Entry in the Race for a Coronavirus Vaccine: Hope". The New York Times.