COVID-19 vaccine

A COVID‑19 vaccine is designed to help protect people from getting very sick, being hospitalized, or dying from the virus that causes COVID‑19. These vaccines work by teaching the body to recognize and fight the virus called SARS-CoV-2.

COVID‑19 vaccines were created very quickly to help stop the COVID-19 pandemic. Scientists used new technologies and also built on past research about other similar viruses, like those that cause coronaviruses, SARS, and MERS. Important awards, such as the 2023 Nobel Prize in Physiology or Medicine, recognized the work that made these vaccines possible.

Some of the main vaccines include the Pfizer–BioNTech mRNA vaccine, Moderna mRNA vaccine, and the Novavax protein subunit vaccine. Because new versions of the virus, called SARS-CoV-2 variants, appeared, these vaccines were updated to better protect against them. People may need extra doses, called booster doses, to keep their protection strong.

Most people who get a COVID‑19 vaccine feel fine, but some might have minor side effects like a sore arm, tiredness, headache, or muscle aches. These feelings usually go away on their own in a few days. Vaccines are safe for everyone, including pregnant people and those who are breastfeeding.

Thanks to these vaccines, many lives were saved. They helped reduce how much the virus spread and made illnesses less severe. Countries around the world worked together to make sure that people, especially those most at risk, could get vaccinated. By August 2024, over 13 billion doses of COVID‑19 vaccines had been given to people worldwide.

Background

Before COVID-19, creating a vaccine for a new disease took many years, and there were no vaccines for human coronavirus infections. However, scientists had made vaccines for some animal diseases caused by similar viruses.

Researchers had previously worked on vaccines for two serious human diseases, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), but these vaccines were only tested on animals. By March 2020, one MERS vaccine had started early human testing.

Some vaccines use a weakened virus grown in eggs, which takes a long time to make. But a different kind of vaccine, using mRNA, can be made much faster. Scientists had been studying mRNA for many years, and companies like Moderna began testing mRNA vaccines before the COVID-19 pandemic. Another type of vaccine, called viral vector vaccines, was also used for COVID-19 after being approved for other diseases like Ebola.

Vaccine technologies

COVID-19 vaccines were developed quickly to help stop the spread of the virus. The first vaccines focused on stopping serious illness. Most needed two doses, but some only needed one dose, like Convidecia and the Janssen COVID-19 vaccine.

Scientists used many different methods to make these vaccines. One important target was the coronavirus spike protein, which helps the virus enter our cells. Vaccines teach our bodies to recognize and fight the virus if we are exposed to it.

mRNA vaccines

Further information: mRNA vaccine

Some vaccines, like Pfizer–BioNTech and Moderna, use a tiny piece of the virus’s genetic material called mRNA. This mRNA tells our cells to make a piece of the virus, which helps our immune system learn to fight it. These vaccines were the first to be approved in many countries.

Viral vector vaccines

Viral vector vaccines use a harmless version of another virus to carry pieces of the COVID-19 virus into our cells. This helps our immune system learn to fight the real virus. Examples include the Oxford–AstraZeneca COVID-19 vaccine and the Sputnik V COVID-19 vaccine.

Inactivated virus vaccines

Some vaccines use whole virus particles that have been treated so they can’t cause illness. These vaccines still help our bodies learn to fight the virus. Examples include CoronaVac and the Sinopharm BIBP vaccine.

Subunit vaccines

Other vaccines use only small pieces of the virus, called antigens. These pieces teach our immune system to recognize the virus without using the whole virus. Examples include Corbevax and the Novavax COVID-19 vaccine.

Other types

Scientists are also studying other ways to make vaccines, including using different viruses or pieces of DNA. Some research looked at whether older vaccines might help, but they did not work well against COVID-19.

Authorized vaccines

Main article: List of COVID-19 vaccine authorizations

By the end of 2022, 50 COVID-19 vaccines had been approved or allowed for emergency use in different countries.

The World Health Organization keeps track of virus changes and how well updated vaccines work against them. As of May 2025, the WHO suggests that vaccines targeting JN.1 or KP.2 are good choices, and LP.8.1 can also be used. The European Medicines Agency suggests updating COVID-19 vaccines to target LP.8.1 for the 2025/2026 vaccination campaign. The US FDA advised that from fall 2025, COVID-19 vaccines should target the JN.1 strain, preferably using the LP.8.1 version.

Combination vaccines

A combined messenger RNA vaccine to protect against both influenza and COVID-19 was introduced in 2026.

Delivery methods

Most coronavirus vaccines are given by intramuscular injection, but scientists are also looking at other ways to give future vaccines.

One new method being studied is called intranasal vaccination. These vaccines target the lining inside the nose, which is a place where viruses can enter the body. They work by helping the nose create special defenses without needing needles, which can be helpful for people who are afraid of needles.

Several intranasal COVID‑19 vaccines are being tested in clinical trials. The first one approved for use was Razi Cov Pars in Iran in October 2021. Later, Russia approved a nasal version of the Sputnik V vaccine in April 2022. In September 2022, India and China approved two nasal vaccines (iNCOVACC and Convidecia), and China approved another one called Pneucolin in December 2022.

Universal vaccine

Main article: Universal coronavirus vaccine

A universal coronavirus vaccine would work against all coronaviruses and maybe even other viruses. In March 2022, the White House suggested speeding up the creation of such a vaccine.

One example of this type of vaccine is being made at the Walter Reed Army Institute of Research. It uses a special tiny particle called a spike ferritin-based nanoparticle (SpFN). Testing of this vaccine began in April 2022, and results were shared in May 2024. Other vaccines in testing include OVX033 and PanCov in France, pEVAC-PS in the UK, and VBI-2902 in Canada.

Another idea is to connect pieces from many different virus strains to a tiny support structure. This might help protect against more strains by focusing on a key part of the virus instead of the whole structure.

Development

In June 2025, the European Medicines Agency shared public data from applications for two COVID‑19 vaccines called Comirnaty and Spikevax.

Creating a COVID‑19 vaccine involved many important steps. These included checking that the vaccines were safe, making sure they worked well, deciding how many doses people needed, and figuring out the best ways to store and deliver them. Scientists also had to work quickly because of the urgent need for a vaccine during the pandemic.

There were special challenges in developing these vaccines quickly. Normally, testing a vaccine takes many years, but during the pandemic, scientists worked on many steps at the same time to speed things up. This made it harder to find enough people to test the vaccines, especially as the spread of the virus changed over time. Countries and companies around the world worked together to support vaccine development, with groups like the Access to COVID‑19 Tools Accelerator, led by the World Health Organization, helping to share resources and knowledge. Governments, such as those in Canada, China, the United Kingdom, and the United States, also provided funding and support to speed up the process. Large drug companies joined forces with smaller biotechnology firms to help make and test the vaccines faster.

Effectiveness

COVID-19 vaccines help protect people from getting very sick, being hospitalized, or dying from the virus. They work best against severe illness, but they also help lower the chance of catching the virus, especially soon after getting vaccinated. Over time, the protection from vaccines can go down, but getting booster shots helps bring protection back up.

Different versions of the virus, like Omicron, can sometimes get around the protection from vaccines, but vaccines still keep people from getting very sick. Mixing different types of COVID-19 vaccines, called heterologous vaccination, also works well and gives strong protection. Vaccines may also help lower the chance of getting long COVID, a condition where symptoms last a long time after the infection.

Adverse effects

The risks of serious illness from COVID-19 are much higher than any risk from the vaccines. For most people, side effects from COVID-19 vaccines are mild and can be taken care of at home. These side effects are similar to those from other vaccines, and serious side effects are very rare.

Common side effects include soreness at the place where the shot was given, feeling tired, having a headache, and muscle or joint pain. These usually get better on their own within a few days. Some people might feel these effects more strongly after the second dose of the vaccine. The vaccines are safe for everyone, including those who are breastfeeding. Some women have noticed small changes in their monthly cycles after getting the vaccine, but these changes go back to normal after a couple of cycles.

Serious side effects are rare but are watched closely by health experts around the world. Studies show that the benefits of getting the vaccine far outweigh any small risks. For example, getting COVID-19 itself is much more likely to cause serious health problems than the vaccine.

Distribution and access

Distribution

Main article: Deployment of COVID-19 vaccines

The number of people who have had at least one dose of a COVID-19 vaccine varies a lot around the world. Some places have many doses, while others have very few. This difference can make the total number of vaccinated people look higher than the actual population of a country.

Access during the pandemic

Further information: Deployment of COVID-19 vaccines § Equitable access, TRIPS Agreement waiver, and COVAX

Getting vaccines has not been fair for everyone. Some countries got many doses early, while others got very few. This unfairness has hurt both rich and poor countries.

Some countries bought vaccines before they were even available. By November 2020, rich countries had bought most of the early vaccines, even though they are only a small part of the world’s population.

In January 2021, a leader at the World Health Organization pointed out that many rich countries had given out thousands of doses, while some of the poorest countries had only given out just a few.

In March 2021, the United States tried to stop Brazil from buying a different vaccine, worried about influence from another country. Some places had trouble getting vaccines because of disagreements between countries.

In Egypt, vaccines were expensive for many people, and a lawyer asked the government to make them free for everyone.

Experts say that to stop the virus, the whole world needs to be vaccinated, not just one country. Some people are asking richer countries to share their extra vaccines because if the virus spreads in poor countries, it can change and become harder for vaccines to work.

In May 2021, the United States said it would support sharing vaccine recipes to help make more vaccines for poor countries. In July 2021, leaders from several global groups said it’s very important to get vaccines to everyone to end the pandemic.

In August 2021, the World Health Organization asked rich countries to wait on giving extra doses until poor countries get more. But some countries planned to give extra doses to their people anyway.

Even though vaccines are very good at preventing serious illness, it’s still important for everyone to keep using safety measures like washing hands and staying apart, especially when there are many cases in the community. This helps protect people who are more likely to get very sick.

COVID-19 vaccine distribution by country

	Location	Vaccinated	Percent
	World	5,645,247,500	70.71%
	China	1,318,026,800	92.48%
	India	1,027,438,900	72.08%
	European Union	338,481,060	75.43%
	United States	270,227,170	79.12%
	Indonesia	204,419,400	73.31%
	Brazil	189,643,420	90.17%
	Pakistan	165,567,890	67.94%
	Bangladesh	151,507,170	89.45%
	Japan	104,740,060	83.79%
	Mexico	97,179,496	75.56%
	Nigeria	93,829,430	42.05%
	Vietnam	90,497,670	90.79%
	Russia	89,081,600	61.19%
	Philippines	82,684,776	72.55%
	Iran	65,199,830	72.83%
	Germany	64,876,300	77.15%
	Turkey	57,941,052	66.55%
	Thailand	57,005,496	79.47%
	Egypt	56,907,320	50.53%
	France	54,677,680	82.50%
	United Kingdom	53,806,964	78.92%
	Ethiopia	52,489,510	41.86%
	Italy	50,936,720	85.44%
	South Korea	44,764,956	86.45%
	Colombia	43,012,176	83.13%
	Myanmar	41,551,930	77.30%
	Argentina	41,529,056	91.46%
	Spain	41,351,230	86.46%
	Canada	34,742,936	89.49%
	Tanzania	34,434,932	53.21%
	Peru	30,563,708	91.30%
	Malaysia	28,138,564	81.10%
	Nepal	27,883,196	93.83%
	Saudi Arabia	27,041,364	84.04%
	Morocco	25,020,168	67.03%
	South Africa	24,210,952	38.81%
	Poland	22,984,544	59.88%
	Mozambique	22,869,646	70.03%
	Australia	22,231,734	84.85%
	Venezuela	22,157,232	78.54%
	Uzbekistan	22,094,470	63.24%
	Taiwan	21,899,240	93.51%
	Uganda	20,033,188	42.34%
	Afghanistan	19,151,368	47.20%
	Chile	18,088,516	92.51%
	Sri Lanka	17,143,760	75.08%
	Democratic Republic of the Congo	17,045,720	16.65%
	Angola	16,550,642	46.44%
	Ukraine	16,267,198	39.63%
	Ecuador	15,345,791	86.10%
	Cambodia	15,316,670	89.04%
	Sudan	15,207,452	30.79%
	Kenya	14,494,372	26.72%
	Ghana	13,864,186	41.82%
	Ivory Coast	13,568,372	44.64%
	Netherlands	12,582,081	70.27%
	Zambia	11,711,565	58.11%
	Iraq	11,332,925	25.72%
	Rwanda	10,884,714	79.74%
	Kazakhstan	10,858,101	54.20%
	Cuba	10,805,570	97.70%
	United Arab Emirates	9,991,089	97.55%
	Portugal	9,821,414	94.28%
	Belgium	9,261,641	79.55%
	Somalia	8,972,167	50.40%
	Guatemala	8,937,923	50.08%
	Tunisia	8,896,848	73.41%
	Guinea	8,715,641	62.01%
	Greece	7,938,031	76.24%
	Algeria	7,840,131	17.24%
	Sweden	7,775,726	74.14%
	Zimbabwe	7,525,882	46.83%
	Dominican Republic	7,367,193	65.60%
	Bolivia	7,361,008	60.95%
	Israel	7,055,466	77.51%
	Czech Republic	6,982,006	65.42%
	Hong Kong	6,920,057	92.69%
	Austria	6,899,873	76.12%
	Honduras	6,596,213	63.04%
	Belarus	6,536,392	71.25%
	Hungary	6,420,354	66.30%
	Nicaragua	6,404,524	95.15%
	Niger	6,248,483	24.69%
	Switzerland	6,096,911	69.34%
	Burkina Faso	6,089,089	27.05%
	Laos	5,888,649	77.90%
	Sierra Leone	5,676,123	68.58%
	Romania	5,474,507	28.56%
	Malawi	5,433,538	26.42%
	Azerbaijan	5,373,253	52.19%
	Tajikistan	5,328,277	52.33%
	Singapore	5,287,005	93.58%
	Chad	5,147,667	27.89%
	Jordan	4,821,579	42.83%
	Denmark	4,746,522	80.41%
	El Salvador	4,659,970	74.20%
	Costa Rica	4,650,636	91.52%
	Turkmenistan	4,614,869	63.83%
	Finland	4,524,288	81.24%
	Mali	4,354,292	18.87%
	Norway	4,346,995	79.66%
	South Sudan	4,315,127	39.15%
	New Zealand	4,302,330	83.84%
	Republic of Ireland	4,112,237	80.47%
	Paraguay	3,995,915	59.11%
	Liberia	3,903,802	72.65%
	Cameroon	3,753,733	13.58%
	Panama	3,746,041	85.12%
	Benin	3,697,190	26.87%
	Kuwait	3,457,498	75.33%
	Serbia	3,354,075	49.39%
	Syria	3,295,630	14.67%
	Oman	3,279,632	69.33%
	Uruguay	3,010,464	88.78%
	Qatar	2,852,178	98.61%
	Slovakia	2,840,017	51.89%
	Lebanon	2,740,227	47.70%
	Madagascar	2,710,365	8.90%
	Senegal	2,684,696	15.21%
	Central African Republic	2,600,389	51.01%
	Croatia	2,323,025	59.46%
	Libya	2,316,327	32.07%
	Mongolia	2,284,018	67.45%
	Togo	2,255,579	27.95%
	Bulgaria	2,155,863	31.58%
	Mauritania	2,103,754	43.15%
	Palestine	2,012,767	37.94%
	Lithuania	1,958,299	69.52%
	Botswana	1,951,054	79.96%
	Kyrgyzstan	1,736,541	24.97%
	Georgia	1,654,504	43.60%
	Albania	1,349,255	47.72%
	Latvia	1,346,184	71.57%
	Slovenia	1,265,802	59.84%
	Bahrain	1,241,174	80.94%
	Armenia	1,150,915	39.95%
	Mauritius	1,123,773	88.06%
	Moldova	1,109,524	36.50%
	Yemen	1,050,202	2.75%
	Lesotho	1,014,073	44.36%
	Bosnia and Herzegovina	943,394	29.44%
	Kosovo	906,858	52.79%
	Timor-Leste	886,838	64.77%
	Estonia	870,202	64.45%
	Jamaica	859,773	30.28%
	North Macedonia	854,570	46.44%
	Trinidad and Tobago	754,399	50.43%
	Guinea-Bissau	747,057	35.48%
	Fiji	712,025	77.44%
	Bhutan	699,116	89.52%
	Republic of the Congo	695,760	11.53%
	Macau	679,703	96.50%
	Gambia	674,314	25.58%
	Cyprus	671,193	71.37%
	Namibia	629,767	21.79%
	Eswatini	526,050	43.16%
	Haiti	521,396	4.53%
	Guyana	497,550	60.56%
	Luxembourg	481,957	73.77%
	Malta	478,953	90.68%
	Brunei	451,149	99.07%
	Comoros	438,825	52.60%
	Djibouti	421,573	37.07%
	Maldives	399,308	76.19%
	Papua New Guinea	382,020	3.74%
	Cabo Verde	356,734	68.64%
	Solomon Islands	343,821	44.02%
	Gabon	311,244	12.80%
	Iceland	309,770	81.44%
	Northern Cyprus	301,673	78.80%
	Montenegro	292,783	47.63%
	Equatorial Guinea	270,109	14.98%
	Suriname	267,820	42.98%
	Belize	258,473	64.18%
	New Caledonia	192,375	67.00%
	Samoa	191,403	88.91%
	French Polynesia	190,908	68.09%
	Vanuatu	176,624	56.42%
	Bahamas	174,810	43.97%
	Barbados	163,853	58.04%
	Sao Tome and Principe	140,256	61.97%
	Curaçao	108,601	58.59%
	Kiribati	100,900	77.33%
	Aruba	90,546	84.00%
	Seychelles	88,520	70.52%
	Tonga	87,375	83.17%
	Jersey	84,365	81.52%
	Isle of Man	69,560	82.66%
	Antigua and Barbuda	64,290	69.24%
	Cayman Islands	62,113	86.74%
	Saint Lucia	60,140	33.64%
	Andorra	57,913	72.64%
	Guernsey	54,223	85.06%
	Bermuda	48,554	74.96%
	Grenada	44,241	37.84%
	Gibraltar	42,175	112.08%
	Faroe Islands	41,715	77.19%
	Greenland	41,227	73.60%
	Saint Vincent and the Grenadines	37,532	36.77%
	Burundi	36,909	0.28%
	Saint Kitts and Nevis	33,794	72.31%
	Dominica	32,995	49.36%
	Turks and Caicos Islands	32,815	71.54%
	Sint Maarten	29,788	70.65%
	Monaco	28,875	74.13%
	Liechtenstein	26,771	68.05%
	San Marino	26,357	77.26%
	British Virgin Islands	19,466	50.76%
	Caribbean Netherlands	19,109	66.69%
	Cook Islands	15,112	102.48%
	Nauru	13,106	110.86%
	Anguilla	10,858	76.45%
	Tuvalu	9,763	97.51%
	Wallis and Futuna	7,150	62.17%
	Saint Helena, Ascension and Tristan da Cunha	4,361	81.23%
	Falkland Islands	2,632	74.88%
	Tokelau	2,203	95.29%
	Montserrat	2,104	47.01%
	Niue	1,638	88.83%
	Pitcairn Islands	47	100.00%
	North Korea	0	0.00%
Number of people who have received at least one dose of a COVID-19 vaccine (unless noted otherwise). Percentage of population that has received at least one dose of a COVID-19 vaccine. May include vaccination of non-citizens, which can push totals beyond 100% of the local population. Countries which do not report data for a column are not included in that column's world total. Vaccination note: Countries which do not report the number of people who have received at least one dose are not included in the world total. Does not include special administrative regions (Hong Kong and Macau) or Taiwan. Data on member states of the European Union are individually listed, but are also summed here for convenience. They are not double-counted in world totals. Vaccination note: Includes Freely Associated States Vaccination note: Includes Vatican City

Technology-assisted vaccine hunting

When COVID-19 vaccines first became available in early 2021, there were not enough appointments for everyone who wanted one. Rules about who could get a vaccine changed often, and different places had their own ways of signing people up.

To help people find open appointments, groups of volunteers started sharing tips and updates on social media. Some people even made computer programs to watch for open spots and send alerts when they found them. These tools helped people in many areas keep track of where and when vaccines were available.

As more vaccines became available and rules changed, many of these tools were no longer needed and stopped working. Some people worried that these tools only helped those who had computers and fast internet, but they were useful while there were not enough vaccines for everyone.

Liability

Some governments made sure that companies that made COVID-19 vaccines would not be sued for most problems that might happen with the vaccines. This meant that if someone had a bad reaction, they could not sue the companies unless the companies did something very wrong on purpose. This rule was in place to help make sure vaccines were made and available quickly during the pandemic. Different countries had different rules about this, but many agreed to protect the companies from most lawsuits.

Public acceptance and hesitancy

Some people were unsure or worried about getting the COVID-19 vaccine. For example, in the Philippines, some messages online tried to make people doubt a vaccine made by a company in China. These messages used unfair claims, like saying the vaccine had ingredients that some religions might not allow. This made it harder for everyone to trust and use the vaccine.