What to Expect After Your COVID-19 Vaccine

Getting vaccinated is the best way to protect you and your family from getting seriously ill with COVID-19. After your vaccine shots, you may experience some side effects. The most common ones are a sore arm, muscle aches, headache, feeling tired, chills or fever.

Similar side effects are reported in adults and children. Even if the side effects are strong enough to affect your daily activities, they should go away in a few days and aren’t a sign you have COVID-19. The available vaccines don’t contain live coronavirus and can’t make you sick with COVID-19. The vaccine doesn’t work immediately.

If you develop symptoms including fever, sore throat, stuffy nose, altered taste or smell, cough, breathing problems, diarrhea or vomiting, these might mean that you’ve developed a COVID-19 infection before the vaccine started working. Consider getting a PCR or antigen test and isolating if you think you may have COVID.

If you think you’re having a severe allergic reaction, call 911 immediately.

When to Call Your Doctor

Call your primary care provider or your child’s pediatrician if symptoms continue to worsen, new symptoms are experienced that aren’t listed above, or the shot area gets increasingly red and tender after 24 hours.

According to the CDC and the U.S. FDA, if you’ve received the Janssen/J&J vaccine watch for possible symptoms of a blood clot with low platelets. Although rare, these symptoms may develop within three weeks of receiving the vaccine and include severe headache or blurred vision, chest pain, abdominal pain, leg swelling, shortness of breath or easy bruising or blood spots under the skin by the injection site. Most people who developed these blood clots and low levels of platelets were women ages 18 through 49 years. If you develop one or more of these symptoms, seek medical care right away, call 911 or go to the nearest emergency room. The FDA also noted an increased risk of Guillain-Barre syndrome in people who received the Johnson & Johnson vaccine.

Building Immunity

Side effects are a sign your body is building immunity. For the Pfizer and Moderna mRNA vaccines to be most effective, two primary shots and an booster 5 months later is recommended (currently boosters are for ages 12+ only). Unless a provider tells you not to, you should get the second and third shots of the mRNA vaccine, even if you have some side effects after the first one.

Remember that it takes time for your body to build protection after vaccination. You’ll have maximum protection from the virus 14 days after you get the second shot of an mRNA vaccine and one week after the booster.

For the viral vector J&J vaccine, only one shot is required for the initial dose. A booster is strongly recommended two months after the first shot. The CDC advises that in most cases, the mRNA vaccines are preferable to the J&J vaccine. 

Helpful Tips

You can alleviate most side effects through simple measures at home. Taking acetaminophen (Tylenol) after your vaccination can help reduce symptoms like fever and aches. For soreness in your arm, apply a cool, wet washcloth where you got the shot. Using and exercising your arm can also help. Contact your doctor or book a Video Visit if the redness or tenderness where your shot was given gets worse after 24 hours or your side effects are severe and don’t go away in a few days.