COVID-19 (Coronavirus)

The coronavirus disease 2019 (COVID-19) pandemic disrupted our lives and our healthcare systems, accounting for millions of illnesses across the globe that ranged from mild to severe to deadly. COVID-19 vaccination is a critical tool to end this pandemic.

COVID-19 vaccines are designed to teach your body’s immune system to recognize and fight off the virus that causes COVID-19, and are the best way to protect yourself and others from this disease, as well as prevent new variants of COVID-19. Millions of people in the United States have received COVID-19 vaccines. COVID-19 vaccines are now widely available for people ages 5 years and older. CDC recommends boosters for everyone 16 and older.

None of these vaccines can give you COVID-19 disease. Information about COVID-19 vaccines will be updated as new information becomes available.

Why are COVID-19 vaccines important?

COVID-19 has sickened and killed millions of people worldwide. Vaccination remains the best way to protect yourself and reduce the spread of the virus and help prevent new variants from emerging. COVID-19 vaccines are a critical tool in stopping the pandemic, resuming normal life, and protecting ourselves and others from this disease.

What is COVID-19?

COVID-19 is caused by a virus called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). It is caused by a strain of coronavirus not previously seen in humans. Coronaviruses, named for the crown-like spikes on their surfaces, are a large family of viruses, which circulate in humans and other animals such as pigs, bats, and cats.

SARS-CoV-2 is the third novel coronavirus to emerge in this century and infect humans (the original SARS outbreak emerged in China in 2003 and the Middle East Respiratory Syndrome Coronavirus emerged in Saudi Arabia in 2012). It was first reported in Wuhan, China, in December 2019. COVID-19 was declared a global pandemic by the World Health Organization in March 2020. The United States declared a public health emergency for the COVID-19 pandemic in March 2020 as well.

SARS-CoV-2 spreads easily from person-to-person when people are in close contact, mainly through respiratory droplets produced when an infected person coughs, sneezes, or talks. To a less extent, the virus can also spread by people who touch contaminated surfaces or objects such as handrails and doorknobs, then touching their eyes, noses, or mouths without washing their hands first.

People with COVID-19 may not know that they are spreading it. People who are infected with the virus that causes COVID-19 can spread it before they become ill. Some people who are infected might not exhibit symptoms but can spread the virus to other people. However, COVID-19 can be serious.

Symptoms of COVID-19 include:

  • Fever or chills
  • Cough
  • Fatigue
  • Loss of taste or smell
  • Difficulty breathing
  • Muscle or body aches
  • Headache
  • Pain or pressure in the chest
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea
  • Not able to wake up or stay awake

Learn more about COVID-19.

Who should get COVID-19 vaccines?

Everyone 5 years of age and older is now eligible to get a COVID-19 vaccination.

Who should not get COVID-19 vaccines?

You should not get a coronavirus vaccine if you had a severe allergic reaction to any ingredient in the vaccine (you can find vaccine ingredients on the Moderna, Pfizer, or Janssen fact sheets).

If you had a severe allergic reaction to a COVID-19 vaccine, you should not get an additional dose of that vaccine. Talk to your healthcare provider about getting an additional dose of another COVID-19 vaccine.

You should not get the Janssen vaccine if you had a blood clot along with a low level of platelets (blood cells that help your body stop bleeding) following Janssen COVID-19 vaccine or following AstraZeneca’s COVID-19 vaccine (not authorized or approved in the United States).

You should talk with your healthcare provider before getting vaccinated if you, or the person getting vaccinated:

  • Are sick, not feeling well, or have a fever
  • May have had a serious reaction to a vaccine in the past
  • Have allergies
  • Have myocarditis, an inflammation of the heart muscle
  • Have pericarditis, an inflammation of the lining outside the heart
  • Have a bleeding disorder or are on a blood thinner
  • Are immunocompromised or are taking medicine that affects your immune system
  • Are planning to become pregnant, are pregnant, or are breastfeeding
  • Have ever fainted when getting an injection
  • Received another COVID-19 vaccine

What are the side effects of COVID-19 vaccines?

These COVID-19 vaccines were tested for safety and will continue to be studied to ensure their safety. Most people who have taken COVID-19 vaccines report that side effects are usually mild and go away after several days. However, it is possible for severe and unexpected side effects to occur.

The common side effects may include:

  • Pain, swelling, or redness where the shot was given
  • Feeling tired
  • Headache
  • Muscle pain
  • Chills
  • Joint pain
  • Fever
  • Nausea or vomiting
  • Feeling unwell
  • Tender or swollen lymph nodes

Experiencing these side effects actually means that the vaccine is working to stimulate your body to generate an immune response. Remember, vaccines mimic a natural infection without causing us to become sick. Some people feel their immune response more than others and some people may feel the immune response more after the second dose of the vaccine. Learn more about vaccine side effects.

There is a remote chance that a COVID-19 vaccine could cause a severe allergic reaction. A severe allergic reaction would usually occur within a few minutes to one hour after getting a dose of a COVID-19 vaccine. For this reason, your vaccination provider may ask you to stay at the place where you received your vaccine for monitoring after vaccination.

Signs of a severe allergic reaction can include:

  • Difficulty breathing
  • Swelling of your face and throat
  • A fast heartbeat
  • A bad rash all over your body
  • Dizziness and weakness

If you experience a severe allergic reaction, call 9-1-1, or go to the nearest hospital. Call your vaccination provider or your healthcare provider if you have any side effects that bother you or do not go away.

Please report any potential side effects experienced from COVID-19 vaccination to the Vaccine Adverse Event Reporting System, a program co-managed by the U.S. Centers for Disease Control and Prevention and the Food and Drug Administration to ensure that all recommended vaccines remain safe. The Countermeasure Injury Compensation Program (CICP) may help pay for the costs of medical care and other expenses for people seriously injured from a COVID-19 vaccine. Learn more about the CICP.

These may not be all the possible side effects of a COVID-19 vaccine. Serious and unexpected side effects may occur, as these vaccines are still being studied in clinical trials.

How is COVID-19 vaccine safety being monitored for safety?

A robust vaccine safety monitoring system is in place in the United States for COVID-19 and other vaccines. Learn how our federal partners are working together to ensure the safety of COVID-19 vaccines, which includes developing new safety monitoring systems and additional information sources. All COVID-19 vaccines authorized for use underwent clinical trials in many thousands of study participants, and will continue to be monitored and studied to ensure their safety. Data from these activities are monitored by CDC, FDA and other federal agencies. 

After vaccination, you can sign up for a new health check service on your smartphone, called V-safe from the Centers for Disease Control and Prevention. V-safe uses text messaging and web surveys to check in with vaccine recipients after COVID-19 vaccination. V-safe also provides a reminder to get your second dose of vaccine, if needed, and will follow up with you if you report a medically important event.

Please report any potential side effects experienced from COVID-19 vaccination to the Vaccine Adverse Event Reporting System, a program co-managed by the U.S. Centers for Disease Control and Prevention and the Food and Drug Administration to ensure that all recommended vaccines remain safe.


Get vaccinated

Getting vaccinated is easy. Vaccines are available at the doctor’s office and many pharmacies — and most are covered by insurance.

Find out how to get vaccinated.

Content created by Office of Infectious Disease and HIV/AIDS Policy (OIDP)
Content last reviewed