July 28, 2021


Damascus Center for Theoretical and Civil Rights Studies

COVID-19 vaccine side effects: What to know

For most people, the only side effects of the Pfizer-BioNTech vaccine against COVID-19, rolling out now in California and across the U.S., might be some arm pain where you get the shot, of course, and some flu-like symptoms. Most people in the clinical trial reported that their side effects went away after about two days.

Some reports have surfaced regarding allergic reactions, so people with severe allergies should discuss their health history and any risks with their doctor before getting the shot.

Here’s what Pfizer lists as side effects reported in its clinical trial, along with the percentage of people age 18 to 55 who reported them after the first dose:

  • Redness at injection site (4.5%)
  • Swelling at injection site (5.8%)
  • Pain at injection site (83.1%)
  • Fever (3.7%)
  • Fatigue (47.4%)
  • Headache (41.9%)
  • Chills (14%)
  • Vomiting (1.2%)
  • Diarrhea (11.1%)
  • New or worsened muscle pain (21.3%)
  • New or worsened joint pain (11%)

People older than 55 reported side effects at slightly lower rates. You can read detailed reports about side effects in section 6.1 here.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, discusses side effects of the vaccine at about the 16-minute mark in a video conversation with the editor of the Journal of the American Medical Assn.

As for allergic reactions, the U.S. Centers for Disease Control and Prevention recommends that people who have had severe allergic reactions, such as anaphylaxis, to other vaccines or injectable medications should be monitored for 30 minutes if they receive the shot. (Anaphylaxis is a life-threatening allergic reaction that can occur within minutes of exposure to an allergen.)

The CDC recommends that people who have other allergies, such as to food or pets, should be vaccinated. You’ll talk to your doctor first and be monitored for 15 minutes after your injection.