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COVID-19 Vaccine


Margot L. Savoy

, MD, MPH, Lewis Katz School of Medicine at Temple University

Reviewed/Revised Jul 2023 | Modified Nov 2023

Coronavirus disease 2019 (COVID-19) vaccines provide protection against COVID-19. COVID-19 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more is the disease caused by infection with the SARS-CoV-2 virus. There are multiple COVID-19 vaccines currently in use worldwide (see the UNICEF COVID-19 Vaccine Market Dashboard and WHO Coronavirus [COVID-19] Dashboard). This topic includes only those vaccines currently in use in the United States.

In the United States, the updated 2023–­2024 formulation of the following COVID-19 vaccines are in use:

  • SARS-CoV-2 virus (COVID-19) mRNA vaccine produced by Pfizer-BioNTech recommended for people 6 months and older

  • SARS-CoV-2 virus (COVID-19) mRNA vaccine produced by Moderna recommended for people 6 months and older

  • SARS-CoV-2 virus (COVID-19) recombinant spike protein nanoparticle vaccine produced by Novavax recommended for people 12 years of age and older

The SARS-CoV-2 virus (COVID-19) adenovirus vector vaccine produced by Janssen/Johnson & Johnson is no longer available in the United States (see CDC: Janssen (Johnson & Johnson) COVID-19 Vaccine).

The best way to prevent infection, severe illness, and death from COVID-19 is to be up to date with COVID-19 vaccinations. Unvaccinated people are more likely to die from COVID-19 than vaccinated people.

Administration of COVID-19 Vaccine

For COVID-19 vaccines available for use in the United States, all dose and administration information, including for all age groups and people with special conditions, is available from the CDC at Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or Authorized in the United States.

Side Effects of COVID-19 Vaccine

The COVID-19 vaccines have similar side effects (see CDC: Getting Your COVID-19 Vaccine):

  • Pain, swelling, and redness at the injection site

  • Tiredness

  • Headache

  • Muscle and joint pains

  • Fever and chills

  • Nausea

  • Swollen lymph nodes

Side effects typically last several days.

There is a very small chance of a severe allergic reaction. This usually occurs within a few minutes to 1 hour after getting a dose of the vaccine and may require emergency treatment. If a person develops difficulty breathing, they or someone with them should call for emergency medical care (911 in the United States) or go to the nearest hospital. People who have had severe allergic reactions to other vaccines or injectable medications should discuss the risk of an allergic reaction with their doctor and be observed after receiving the vaccine.

The heart problems myocarditis Myocarditis Myocarditis is inflammation of the muscle tissue of the heart (myocardium) that causes tissue death. Myocarditis may be caused by many disorders, including infection, toxins and drugs that affect... read more and pericarditis Acute Pericarditis Acute pericarditis is inflammation of the pericardium (the flexible two-layered sac that envelops the heart) that begins suddenly, is often painful, and causes fluid and blood components such... read more Acute Pericarditis have been reported after doses of the vaccines made by Pfizer-BioNTech, Moderna, and Novavax, suggesting there may be an increased risk of these problems after vaccination. The risk is highest in young males. Vaccine recipients should seek medical attention right away if they have chest pain, shortness of breath, or feelings of having a fast-beating, fluttering, or pounding heart after vaccination.

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

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