Coronavirus disease (COVID-19): Vaccines and vaccine safety

All COVID-19 vaccines, listed by WHO as for emergency use or prequalified, provide protection against severe disease and death resulting from COVID-19 infection.

There are several types of COVID-19 vaccines, including:

• Inactivated or weakened virus vaccines: These use an inactivated or weakened version of the virus that doesn’t cause disease but still generates an immune response,
• Protein-based vaccines: These contain harmless fragments of proteins or protein shells that mimic the COVID-19 virus to safely generate an immune response,
• Viral vector vaccines: These use a safe virus that cannot cause disease but serves as a vehicle to produce coronavirus proteins to generate an immune response, and
• RNA and DNA vaccines: These are genetically engineered RNA or DNA which create proteins that safely activate an immune response.

For the latest information on vaccines, please visit the  COVID-19 vaccines page.

Watch the “Vaccines Explained” series for an explanation of  the different types of COVID-19 vaccines.

WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) provides timely recommendations on COVID-19 vaccination. SAGE’s latest guidance from November 2023 considers high population immunity from vaccination and/or infection and recommends the following:

• One dose for those who have never received any COVID-19 vaccine, especially those who are at high risk of severe illness such as older persons, adults with chronic diseases, individuals with immunocompromising conditions and health workers with direct patient contact.
• One dose for pregnant persons, during each pregnancy.
• Revaccination 6 to 12 months after the most recent dose for older adults, adults with comorbidities, persons who are immunocompromised and health workers with direct patient contact.
• Revaccination is not routinely recommended to healthy adults, adolescents and children.

  For optimal protection, it is important to receive the recommended COVID-19 vaccine doses. Consult with your health care provider for specific advice.

  Refer to the following WHO page for the latest advice: COVID-19 advice for the public: Getting vaccinated.

  For the latest SAGE Recommendations, refer to the SAGE Roadmap for prioritizing uses of COVID-19 vaccines.

There are very few conditions that would exclude someone from being vaccinated. You should NOT be vaccinated if:

• You have a history of severe allergic reactions/anaphylaxis to any of the ingredients in the COVID-19 vaccines, or
• You have a fever over 38.5 ºC on the day of your vaccine appointment. Postpone until you have recovered.

COVID-19 vaccines are safe for people taking blood thinners. However, prior to being vaccinated, inform the health staff administering the vaccine of any medication that you are taking.

Each vaccine may have specific considerations for certain groups or health conditions, so it would be best to discuss with your health care provider about your specific situation.

• adults over 75 or 80 years old
• adults over 50 or 60 years old with comorbidities
• adults, adolescents and children who are immunocompromised

Healthy children and adolescents ages 6 months to 17 years belong to the low-priority group for COVID-19 vaccination. Vaccinating them at this stage of the pandemic has limited public health impact. Countries can consider vaccinating this group based on disease burden, cost-effectiveness and other public health priorities.

Children and adolescents at higher risk of severe COVID-19 (those who are immunocompromised, with severe obesity or with comorbidities) and never received COVID-19 vaccination should get one dose.

Yes, all WHO emergency-use listed or prequalified COVID-19 vaccines provide protection against severe disease and death from circulating COVID-19 variants. Any of the approved COVID-19 vaccines can be used either for the initial series or revaccination.

Vaccination should not be delayed in anticipation of newer versions of the COVID-19 vaccine. For people at a high risk of getting severe COVID-19, a dose of any available vaccine is more beneficial than delaying vaccination.

A person who had a prior COVID-19 infection and is recommended for vaccination, according to the recent SAGE Roadmap, should still be vaccinated.

Vaccination is recommended for those who have never received any COVID-19 vaccine and are at high risk of severe illness such as older persons, adults with chronic diseases, individuals with immunocompromising conditions and health workers with direct patient contact. Pregnant persons should get one dose.

Revaccination 6 to 12 months after the most recent dose is recommended for older adults, adults with comorbidities, persons who are immunocompromised and health workers with direct patient contact.

Hybrid immunity - the immunity one receives from both vaccination and prior COVID-19 infection - enhances protection against the severe outcomes of future COVID-19 infections and offers longer protection than infection alone.

It is safe for you to receive a COVID-19 vaccine different from the one used for the previous dose(s).

If you’re offered a different type of vaccine, you can go ahead and get vaccinated. Depending on the type of vaccine, using a different type of vaccine may provide better protection than using the same type of vaccine.

Yes. While COVID-19 vaccines are highly effective against serious disease and death, no vaccine is 100% effective.

Vaccinated people can get infected and may fall ill with COVID-19. This is known as a ‘breakthrough infection’ or ‘breakthrough case’. Breakthrough infections can happen with any vaccine and do not mean that the vaccine does not work.

People who get COVID-19 after being vaccinated are much more likely to only experience mild symptoms as effectiveness against serious illness and death remains high. Vaccine effectiveness wanes over time, so it’s important to stay updated with your shots as recommended by your health care provider.

WHO’s Global Advisory Committee on Vaccine Safety (GACVS) monitors how approved vaccines behave in the real world to identify any signals of adverse events following immunization. GACVS is an independent group of experts providing authoritative, scientific advice to WHO on vaccine safety issues of global or regional concern.

Unprecedented scientific collaborations allowed COVID-19 vaccine research, development, and authorizations to be completed in record time – to meet the urgent need for these vaccines during the acute phase of the pandemic – while maintaining high safety standards.

Vaccines must be proven safe and effective in large Phase III clinical trials to prove that they meet internationally agreed benchmarks for safety and efficacy before they are introduced in national immunization programs.

Independent reviews of the efficacy and safety evidence are required by WHO for each vaccine candidate, including regulatory review and approval in the country where the vaccine is manufactured, before WHO considers it approved for emergency use listing or prequalification.

Billions of people have received the COVID-19 vaccine to date, showing that the benefits of COVID-19 vaccinations outweigh the risks of getting ill with COVID-19. Do not delay COVID-19 vaccination if it is recommended for you by your health care provider. Getting vaccinated could protect you from severe illness and save your life.

Like with any vaccine, some people will experience mild to moderate side effects after being vaccinated against COVID-19. This is a normal sign that the body is developing protection.

Side effects of COVID-19 vaccines include fever, tiredness, headache, muscle ache, chills, diarrhoea and pain or redness at the injection site.

Not everyone will experience side effects. Most side effects go away within a few days on their own. You can manage any side effects with rest, plenty of non-alcoholic liquids and taking medication to manage pain and fever, if needed.

More serious or long-lasting side effects of COVID-19 vaccines are possible but extremely rare. National health authorities monitor vaccines to detect and respond to rare adverse events. At the regional and global level, WHO also supports countries in monitoring vaccine safety.

Yes, WHO recommends a single dose of the COVID-19 vaccine during each pregnancy. Pregnant persons are at a higher risk from COVID-19, which can affect both them and the baby.

Vaccination during pregnancy is safe. It also benefits the baby, as it allows the antibodies created to be passed from mother to child. These antibodies can also help protect the baby for the first few months of life.

The COVID-19 vaccine can be safely given at any time during pregnancy to avoid missing opportunities. Vaccination in the mid-second trimester maximizes protection. Additionally, COVID-19 vaccines can be safely administered with other vaccines recommended during pregnancy. 

You can learn more about COVID-19 vaccines and pregnancy here.

If you are breastfeeding, you should get vaccinated against COVID-19 with the available vaccine according to your national recommendations.

None of the current COVID-19 vaccines have live virus in them. This means there is no risk of you passing COVID-19 to your baby through your breastmilk. In fact, the antibodies you get after vaccination may go through your breast milk and help to protect your baby.

Yes, you should get vaccinated if you are planning to get pregnant.

There is no evidence that suggests the COVID-19 vaccines interfere with fertility. There is currently no biological evidence that antibodies from COVID-19 vaccination or vaccine ingredients could cause any problems with reproductive organs.