Common vaccine side-effects
Contact your doctor if you have:
Tips to help with vaccine side-effects
Serious vaccine side effects are rare but may occur. For more information see Safety of COVID-19 Vaccines and Selected Adverse Events Reported after COVID-19 Vaccination.
Severe allergic reactions
As with any medicine, it is rare but possible to have a serious allergic reaction. A severe allergic reaction will usually occur within a few minutes to one hour after getting a vaccine. For this reason, your vaccination provider may ask you to stay at the place where you received your vaccine for monitoring. Signs of a severe allergic reaction can include:
It is very unlikely that this will happen. If it does, call 911 or go to the nearest emergency room.
Rare blood clots and low platelets after Johnson & Johnson/Jansen COVID-19 vaccine
Blood clots involving blood vessels in the brain, abdomen, and legs along with low levels of platelets (blood cells that help your body stop bleeding), have occurred in some people who have received the Johnson & Johnson/Janssen COVID-19 vaccine. This condition is called thrombosis with thrombocytopenia syndrome (TTS). It has been reported in males and females across a wide age range, with most reports in females ages 30-49 years. Symptoms usually begin about one to two weeks after getting a vaccine. The chance of this happening is very low.
You should seek medical attention right away if you have any of the following symptoms after receiving the Johnson & Johnson vaccine:
Myocarditis & Pericarditis after Pfizer, Moderna, or Novavax
There is a rare risk of inflammation of the heart muscle (myocarditis) or outer lining of the heart (pericarditis) in some people who got the Pfizer, Moderna, or Novavax vaccine.
Both myocarditis and pericarditis have the following symptoms:
Myocarditis and pericarditis are more common after the second vaccine dose. But getting the second vaccine dose later (at 8 weeks) may lower the risk of these rare heart problems.
Most patients with myocarditis and pericarditis who received care improved with medicine and rest and felt better quickly.
Get medical care if you or your child have symptoms of myocarditis or pericarditis especially if it’s within a week after COVID-19 getting a vaccine.
It is important to note that getting COVID-19 is also connected with an increased risk of myocarditis and pericarditis. Plus, getting COVID is also linked with a higher risk of stroke, acute coronary syndrome, heart attack (myocardial infarction), heart failure, irregular heartbeat (arrhythmia), and cardiac death.
For more information, visit the CDC webpage Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination.
Guillain Barré Syndrome after J&J vaccine
There have been rare cases of Guillain Barré syndrome in some people who got the Johnson & Johnson (Janssen) COVID-19 Vaccine. Guillain Barré syndrome is a nervous system disorder in which the body’s immune system damages nerve cells, causing muscle weakness and sometimes paralysis. Most of the cases were in men ages 50 years and older.
Seek medical attention right away if you develop any of the following symptoms:
Help CDC monitor the safety of COVID-19 vaccines.
Sign up at vsafe.cdc.gov
V-safe provides quick and confidential health check-ins via text message and/or web survey. You can easily share information with CDC about how you (or your child feel) after getting a COVID-19 vaccine.
After you enroll, during the first week after you get your vaccine, v-safe will send you a text message each day to ask how you are feeling. After that, you will receive fewer health check-ins. Depending on your answers, someone from CDC may call to get more information. V-safe is available in multiple languages.
Learn more about v-safe.
If you have an adverse event (possible side effect) after you are vaccinated, even if you aren't sure that the vaccine caused it, please report it to VAERS. The Vaccine Adverse Event Reporting System is an early warning system that the FDA and CDC use to detect possible safety problems. To make a report, call 1-800-822-7967 or visit https://vaers.hhs.gov/reportevent.html. Please note that VAERS does not provide medical advice.