Skip to main content


All stories

Q: I've read that there can be side effects to the COVID-19 vaccine. What are they?

The Food and Drug Administration has released the COVID-19 vaccines under an emergency use authorization and the vaccines are being distributed across the country. Studies found that these vaccines are 94-95% effective at preventing COVID-19 after two doses.

Some people have reported minor, short lived side effects from the vaccine. The most common reported side effect has been a reaction around the injection site, including pain, redness, warmth, or mild swelling.

Other common side effects include short-term fatigue, headache, and muscle pain. These symptoms are usually mild. A smaller number of people reported temporary chills or a low fever. Side effects tended to be worse after the second dose of the vaccine.

Remember that the vaccine works by stimulating your immune system to recognize and fight off the COVID-19 virus. Side effects are caused by your immune system kicking into gear. Unlike the symptoms caused by an actual COVID infection, they are mild and temporary. So, although the side effects might be unpleasant, they are a sign that the vaccine is working.

Because of the possible side effects, it's a good idea to schedule your vaccinations for a time when you can rest or stay home to recover. Side effects can be treated with an over-the-counter medication like Tylenol or ibuprofen. Contact your healthcare provider if side effects become more serious.

While it is extremely rare, some people can have a severe allergic reaction to vaccines. If you had severe allergic reactions to any other vaccine or medication, discuss the vaccine and your options with your doctor first. If you received the vaccine and believe you may be having a severe allergic reaction, call 911 and seek emergency medical care immediately.

Michael J. Shea , MD

Critical Care Medicine

Maui Memorial Medical Center
221 Mahalani Street
Wailuku, HI 96793