It’s totally normal to experience side effects from COVID-19 vaccines and William Moss can explain what you need to know.

COVID-19 vaccines are the first to be produced using the mRNA platform. These vaccines are highly effective, but they are also “reactogenic,” meaning that they’re likely to cause a noticeable immune response.

Here, Moss, an expert epidemiologist and executive director of the International Vaccine Access Center at Johns Hopkins University, explains what side effects to expect after a COVID-19 vaccination, what to know before and after your vaccination, and when to contact your doctor or a medical professional:

What side effects should I expect from COVID-19 vaccines?

Side effects may vary with the type of COVID-19 vaccine. We know the most about side effects following vaccination with the Pfizer and Moderna messenger RNA—or mRNA—vaccines.

The most common side effect is soreness at the site of injection. Other side effects include fatigue, headache, muscle aches, chills, joint pain, and possibly some fever.

How long do side effects last?

Usually 24 to 48 hours, and no more than a few days.

Why do these vaccines seem to have more noticeable side effects than the flu vaccine? How do they compare to other vaccines’ side effects—like the shingles vaccine, for example?

These side effects are typical of the inflammation induced by vaccines and are a sign of the body’s immune response to the vaccine.

Some vaccines are more reactogenic—the term used to describe these types of side effects—and some people have more severe reactions than others. The side effects of COVID-19 vaccines are similar to what is observed after the shingles vaccine.

Read the full article about  side effects of the COVID-19 vaccine from Johns Hopkins University at Futurity.