COVID-19 vaccine

COVID-19 vaccine

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 platforms 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 severity and death caused by COVID‑19. 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.

As of 17 January 2022, 9.68 billion doses of COVID‑19 vaccines have been administered worldwide based on official reports from national public health agencies. 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.


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).

Vaccines that use an inactive or weakened virus that has been grown in eggs typically take more than a decade to develop. In contrast, mRNA is a molecule that can be made quickly, and research on mRNA to fight diseases was begun decades before the COVID‑19 pandemic by scientists such as Drew Weissman and Katalin Karikó, who tested on mice. Moderna began human testing of an mRNA vaccine in 2015. Viral vector vaccines were also developed for the COVID‑19 pandemic after the technology was previously cleared for Ebola.

As multiple COVID‑19 vaccines have been authorized or licensed for use, real-world vaccine effectiveness (RWE) is being assessed using case control and observational studies. A study is investigating the long-lasting protection against SARS-CoV-2 provided by the mRNA vaccines.


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.


In November 2021, the full nucleotide sequences of the AstraZeneca and Pfizer/BioNTech vaccines were released by the UK Medicines and Healthcare Products Regulatory Agency, in response to a freedom of information request.

Clinical research

Post-vaccination complications

Vaccine types

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 (S protein) and its variants as the primary antigen of COVID‑19 infection, since the S protein triggers strong B-cell and T-cell immune responses. However, other coronavirus proteins are also being investigated for vaccine development, like the nucleocapsid, because they also induce a robust T-cell response and their genes are more conserved and recombine less frequently (compared to Spike).

Platforms 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 adaptive 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.

mRNA vaccines

Several COVID‑19 vaccines, including the Pfizer–BioNTech and Moderna vaccines, have been developed to use RNA to stimulate an immune response. When introduced into human tissue, the vaccine contains either self-replicating RNA or messenger RNA (mRNA), which both cause cells to express the SARS-CoV-2 spike protein. This teaches the body how to identify and destroy the corresponding pathogen. 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 and Moderna vaccines. The CVnCoV RNA vaccine from CureVac failed in clinical trials.

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. Lipid nanoparticles (LNPs) 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.

On 11 August 2021, the developers of Sputnik V proposed, in view of the Delta case surge, that Pfizer test the Ad26 component (termed its 'Light' version) as a booster shot:

Delta cases surge in US & Israel shows mRNA vaccines need a heterogeneous booster to strengthen & prolong immune response. #SputnikV pioneered mix&match approach, combo trials & showed 83.1% efficacy vs Delta. Today RDIF offers Pfizer to start trial with Sputnik Light as booster.

Inactivated virus vaccines

Inactivated vaccines consist of virus particles that are grown in culture and then 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 and the Sinopharm BIBP and WIBP vaccines; the Indian Covaxin; later this year the Russian CoviVac; the Kazakhstani vaccine QazVac; and the Iranian COVIran Barekat. 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 authorized vaccines of this type are the peptide vaccine EpiVacCorona, ZF2001, MVC-COV1901, and Corbevax. Vaccines with pending authorizations or 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.


Intranasal vaccines target mucosal immunity in the nasal mucosa which is a portal for viral entrance to the body. These vaccines are designed to stimulate nasal immune factors, such as IgA. In addition to inhibiting the virus, nasal vaccines provide ease of administration because no needles (and the accompanying needle phobia) are involved. Nasal vaccines have been approved for other infections, such as influenza. As of 2021, only one nasal vaccine, Flumist (USA); Fluenz Tetra (European Union), had been authorized in the United States and Europe for use as an influenza vaccine.

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.

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.

Turnbull & Asser

Planning and 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.


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 several years. Public health programs have been described as in "[a] race to vaccinate individuals" with the early wave vaccines.

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 was expected to 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.


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 of 96 projects for development and production of vaccines 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.

The United Kingdom government 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. The UK's Vaccine Taskforce contributed to 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 toward effective vaccines.



Adverse events

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. Anaphylaxis has occurred in approximately 2 to 5 people per million vaccinated in the United States. An increased risk of rare and potentially fatal thrombosis events have been associated following the administration of the Janssen (Johnson and Johnson) and Oxford-AstraZeneca COVID‑19 vaccines, with the highest reported rate among females in their 30s and 40s. The rate of thrombosis events following vaccination with the Johnson and Johnson and AstraZeneca vaccines has been estimated at 1 case per 100,000 vaccinations compared to between 0.22 and 1.57 cases per 100,000 per year in the general population. There is no increased risk for thrombotic events after vaccination with mRNA COVID‑19 vaccines like Pfizer and Moderna.

Mix and match

According to studies, the combination of two different COVID-19 vaccines, also called cross vaccination or mix-and-match method, provides protection equivalent to that of mRNA vaccines – including protection against the Delta variant. Individuals who receive the combination of two different vaccines produce strong immune responses, with side effects no worse than those caused by standard regimens.

Duration of immunity

Available data show that fully vaccinated individuals and those previously infected with SARS-CoV-2 have a low risk of subsequent infection for at least 6 months. Data are currently insufficient to determine an antibody titer threshold that indicates when an individual is protected from infection. Multiple studies show that antibody titers are associated with protection at the population level, but individual protection titers remain unknown. For some populations, such as the elderly and the immunocompromised, protection levels may be reduced after both vaccination and infection. Finally, current data suggest that the level of protection may not be the same for all variants of the virus.

As new data continue to emerge, recommendations will need to be updated periodically. It is important to note that at this time, there is no authorized or approved test that providers or the public can use to reliably determine if a person is protected from infection.

Society and culture


Note about table to the right: Number and percentage of people who have received at least one dose of a COVID‑19 vaccine (unless noted otherwise). May include vaccination of non-citizens, which can push totals beyond 100% of the local population. Table is updated daily by a bot.


Countries have extremely unequal access to the COVID-19 vaccine. Vaccine equity has not been achieved, or even approximated. The inequity has harmed both countries with poor access and countries with good access.

Nations pledged to buy doses of the 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.

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."

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 of 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 the 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 a 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 member states and some other members of the World Trade Organization (WTO) 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 US government under President Joe Biden 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.

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. On 15 March, Brazilian journalism agency Agência Pública reported that the country vaccinated about twice as many people who declare themselves white than black and noted that mortality from COVID‑19 is higher 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 Serum Institute of India, 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. In mid-May 2021, UNICEF was also critical of the fact that most proposed donations of Moderna and Pfizer vaccines were not slated for delivery until the second half of 2021, or early in 2022.

On 1 July 2021, the heads of the World Bank Group, the International Monetary Fund, the World Health Organization, and the 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." In July 2021, The BMJ reported that countries have thrown out over 250,000 vaccine doses as supply exceeded demand and strict laws prevented the sharing of vaccines. A survey by The New York Times found that over a million doses of vaccine had been thrown away in ten U.S. states because federal regulations prohibit recalling them, preventing their redistribution abroad. Furthermore, doses donated close to expiration often cannot be administered quickly enough by recipient countries and end up having to be discarded.

Amnesty International and Oxfam International have criticized the support of vaccine monopolies by the governments of producing countries, noting that this is dramatically increasing the dose price by five times and often much more, creating an economic barrier to access for poor countries. Médecins Sans Frontières (Doctors without Borders) has also criticized vaccine monopolies and repeatedly called from their suspension, supporting the TRIPS Waiver. The waiver was first proposed in October 2020, and has support from most countries, but delayed by opposition from EU (especially Germany - major EU countries such as France, Italy and Spain support the exemption), UK, Norway, and Switzerland, among others. MSF called for a Day of Action in September 2021 to put pressure on the WTO Minister's meeting in November, which is expected to discuss the TRIPS IP waiver.

On 4 August 2021, to reduce unequal distribution between rich and poor countries, the WHO called for a moratorium on a booster dose at least until the end of September. However, on 18 August, the United States government announced plans to offer booster doses 8 months after the initial course to the general population, starting with priority groups. Before the announcement, the WHO harshly criticized this type of decision, citing the lack of evidence for the need for boosters, except for patients with specific conditions. At this time, vaccine coverage of at least one dose was 58% in high-income countries and only 1.3% in low-income countries, and 1.14 million Americans already received an unauthorized booster dose. US officials argued that waning efficacy against mild and moderate disease might indicate reduced protection against severe disease in the coming months. Israel, France, Germany, and the United Kingdom have also started planning boosters for specific groups. On 14 September 2021, more than 140 former world leaders, and Nobel laureates, including former President of France François Hollande, former Prime Minister of the United Kingdom Gordon Brown, former Prime Minister of New Zealand Helen Clark, and Professor Joseph Stiglitz, called on the candidates to be the next German chancellor to declare themselves in favour of waiving intellectual property rules for COVID‑19 vaccines and transferring vaccine technologies. In November 2021, nursing unions in 28 countries have filed a formal appeal with the United Nations over the refusal of the UK, EU, Norway, Switzerland, and Singapore to temporarily waive patents for Covid vaccines.

During his first international trip, President of Peru Pedro Castillo spoke at the seventy-sixth session of the United Nations General Assembly on 21 September 2021, proposing the creation of an international treaty signed by world leaders and pharmaceutical companies to guarantee universal vaccine access, arguing "The battle against the pandemic has shown us the failure of the international community to cooperate under the principle of solidarity".

Optimizing the societal benefit of vaccination may benefit from a strategy that is tailored to the state of the pandemic, the demographics of a country, the age of the recipients, the availability of vaccines, and the individual risk for severe disease: In the UK, the interval between prime and boost dose was extended to vaccinate as many persons as early as possible, many countries are starting to give an additional booster shot to the immunosuppressed and the elderly, and research predicts an additional benefit of personalizing vaccine dose in the setting of limited vaccine availability when a wave of virus Variants of Concern hits a country.

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.


Vaccine inequity damages the global economy, disrupting the global supply chain. Most vaccines were being reserved for wealthy countries, as of September 2021, some of which have more vaccine than is needed to fully vaccinate their populations. When people, undervaccinated, needlessly die, suffer disability, and live under lockdown restrictions, they cannot supply the same goods and services. This harms the economies of undervaccinated and overvaccinated countries alike. Since rich countries have larger economies, rich countries may lose more money to vaccine inequity than poor ones, though the poor ones will lose a higher percentage of GDP and suffer longer-term effects. High-income countries would profit an estimated US$4.80 for every $1 spent on giving vaccines to lower-income countries.

The International Monetary Fund sees the vaccine divide between rich and poor nations as a serious obstacle to a global economic recovery. Vaccine inequity disproportionately affects refuge-providing states, as they tend to be poorer, and refugees and displaced people are economically more vulnerable even within those low-income states, so they have suffered more economically from vaccine inequity.


Several governments agreed to shield pharmaceutical companies like Pfizer and Moderna from negligence claims related to COVID‑19 vaccines (and treatments), as in previous pandemics, when governments also took on liability for such claims.

In the US, 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.


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 firm's sole shareholder, which handled "professional, scientific and technical activities", was Erik Prince. In March 2021, COVAXX raised $1.35 billion in a private placement.

Misinformation and hesitancy

See also

  • 2009 swine flu pandemic vaccine
  • COVID‑19 drug development
  • COVID-19_vaccine_clinical_research: Effectiveness
  • COVID‑19 drug repurposing research
  • COVID‑19 vaccine card
  • Universal coronavirus vaccine
  • Vaccine passports during the COVID‑19 pandemic
  • List of COVID-19 vaccine authorizations



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): 179–186. 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. Archived from the original (PDF) on 28 September 2020. Retrieved 21 September 2020.
  • "Protocol AZD1222 – D8110C00001" (PDF). AstraZeneca.
  • "Protocol VAC31518COV3001; Phase 3 (Ensemble)" (PDF). Janssen Vaccines & Prevention.
  • "Protocol VAC31518COV3009; Phase 3 (Ensemble 2)" (PDF). Janssen Vaccines & Prevention.
  • "Protocol VAT00008 – Study of Monovalent and Bivalent Recombinant Protein Vaccines against COVID-19 in Adults 18 Years of Age and Older Protocol" (PDF). Sanofi Pasteur.

External links

  • "The different types of COVID-19 vaccines". World Health Organization (WHO).
  • "COVID-19 vaccine tracker and 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).
  • "Tracking Omicron and Other Coronavirus Variants". The New York Times.
  • M.I.T. Lecture 10: Kizzmekia Corbett, Vaccines on YouTube
  • M.I.T. Lecture 12: Dan Barouch, Covid-19 Vaccine Development 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.
  • "Halting Progress and Happy Accidents: How mRNA Vaccines Were Made". The New York Times.
  • "Coronavirus vaccine – weekly summary of Yellow Card reporting". Medicines and Healthcare products Regulatory Agency (MHRA).
  • "Joint Statement from HHS Public Health and Medical Experts on COVID-19 Booster Shots". U.S. Centers for Disease Control and Prevention (CDC).

COVID-19 vaccine