Vaccine Side Effects

Most people don’t have any serious side effects from vaccines. The most common side effects—like soreness where the shot was given—are usually mild and go away quickly on their own.

What are common side effects of vaccines?

The most common side effects after vaccination are mild. They include:

  • Pain, swelling, or redness where the shot was given
  • Mild fever
  • Chills
  • Feeling tired
  • Headache
  • Muscle and joint aches

Fainting can also happen after any medical procedure, including vaccinations.

Keep in mind that most common side effects are a sign that your body is starting to build immunity (protection) against a disease. Learn more about how vaccines provide immunity.

What about serious side effects?

Serious side effects from vaccines are extremely rare. For example, if 1 million doses of a vaccine are given, 1 to 2 people may have a severe allergic reaction.

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 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.

Keep in mind that getting vaccinated is much safer than getting the diseases vaccines prevent. Learn more about vaccine safety.

What if I feel sick after getting vaccinated?

If you experience a severe allergic reaction, call 9-1-1, or go to the nearest hospital. Talk with your doctor if you’re concerned about your health after getting vaccinated. You or your doctor can choose to report the side effect to the Vaccine Adverse Event Reporting System (VAERS).

In the very rare event that a vaccine causes a serious problem, the National Vaccine Injury Compensation Program (VICP) may offer financial help to individuals who file a petition. Learn more about VICP. 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.

Talk with your doctor if you’re concerned about your health after getting vaccinated. You or your doctor can choose to report the side effect to the Vaccine Adverse Event Reporting System (VAERS).

In the very rare event that a vaccine causes a serious problem, the National Vaccine Injury Compensation Program (VICP) may offer financial help to individuals who file a petition. Learn more about VICP.

Do childhood vaccines cause autism?
No. Vaccines do not cause autism. Many studies have looked for a link between vaccines and autism, and the research clearly shows that vaccines don’t cause autism.
Learn more about these studies and autism.

Find information about specific vaccines and possible side effects.

LAST REVIEWED: March 2021