A-Z Index
Instagram Facebook Twitter Youtube
For Healthcare Providers: COVID-19 Hub Vaccine Hub
For Everyone: VaccinateLACounty.com
vSafe on a phone

Sign up for v-safe, the CDC after-vaccination health checker. Please sign up at vsafe.cdc.gov to tell CDC about any side effects. Click here for more information.

Keep your white vaccine card safe - it is your official vaccination record! See vaccination records webpage for more details.

PDFs Ver página en español
After you get a Pfizer or Moderna vaccine
English | Español | հայերեն | 简体中文 | 한국어

Children under 18: English | Español | հայերեն | 简体中文 | 한국어

After you get a Novavax vaccine:
English | Español | հայերեն | 简体中文 | 한국어
After you get a Johnson & Johnson vaccine:
English | Español | հայերեն | 简体中文 | 한국어
Common vaccination side-effects

Common vaccine side-effects

  • Pain, swelling, andor redness in the arm where the vaccine was given (or thigh for small children)
  • Fever
  • Feeling tired
  • Headache
  • Nausea or loss of appetite
  • Fussiness or crying (small children)
  • Chills
  • Muscle or joint pain
  • Swollen lymph nodes
  • You may get vaccine side-effects in the first 2 days after getting a dose of the vaccine.
  • They may affect your ability to do daily activities, but should go away within a few days.
  • Vaccine side effects are normal and show that your body is learning to fight the virus and build up immunity. Not everyone gets them side-effects.
  • Younger children may have fewer side effects after getting a COVID-19 vaccine than teens or young adults.
  • Side effects are more common after the second dose than the first. So far, side effects reported after getting a booster dose are like those after getting the primary doses.
  • It is important to get all recommended COVID-19 vaccine doses, even if you get side effects after a dose, unless a vaccination provider or your doctor tells you not to.

Contact your doctor if you have:

  • Redness or tenderness where the vaccine was given gets worse after 24 hours
  • Symptoms that get worse or worry you
If you or your child get a COVID-19 vaccine and you think you or they might be having a severe allergic reaction after leaving the vaccination site. Seek immediate medical care by calling 911 or go to the nearest emergency room. See severe allergic reactions to learn more.

Tips to help with vaccine side-effects

  • Apply a clean, cool, wet washcloth to reduce pain and discomfort in your arm. It may also help to use or exercise your arm. To reduce discomfort from fever, drink plenty of fluids and dress lightly.
  • Over-the counter medicines like acetaminophen (Tylenol®) or ibuprofen (Motrin or Advil®) can help if you develop pain, fever, headache, or discomfort.
Rare, serious 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:

  • Difficulty breathing or wheezing
  • Swelling of your tongue or throat
  • A rash or hives over your body
  • A fast heartbeat
  • Dizziness and weakness

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:

  • Shortness of breath
  • Chest pain
  • Leg swelling
  • Persistent abdominal pain
  • Severe or persistent headaches
  • Blurred vision
  • Easy bruising or tiny blood spots under the skin beyond the site of the injection.

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:

  • Chest pain
  • Shortness of breath
  • Feelings of having a fast beating, fluttering, or pounding heart.

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:

  • Weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other parts of the body
  • Trouble walking
  • Difficulty with facial movements, including speaking, chewing, or swallowing
  • Double vision or inability to move eyes
  • Difficulty with bladder control or bowel function
vSafe on a phone
vSafe banner saying: Get vaccinated. Get your smartphone. Get started with v-safe.

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.

How to report an adverse reaction (possible side-effect)

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.

Icon: Get Adobe Reader
Adobe Reader

Note: PDF documents on this site were created using Adobe Acrobat 5.0 or later. Document functionality may be reduced if you are using an earlier version (4.x or less). Get the latest version of Adobe Acrobat.

Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

Los Angeles County Seal: Enriching lives through effective and caring services