What side effects are known and expected for the approved mRNA vaccines?

After over 16 million mRNA vaccine doses administered, Swissmedic has so far evaluated approximately 16'000 reports of side effects.

The most common side effects after receiving the mRNA vaccine include soreness at the injection site, fatigue, headache, muscle soreness, chills, joint pain, nausea, vomiting, and fever. These symptoms occur up to seven days post vaccination and tend to be stronger after the second dose.

Reports of serious allergic reactions are extremely rare. A report issued by the Center for Disease Control and Prevention (CDC) in the United States indicates that, on average, 1 person in 100,000 (Pfizer/Biontech vaccine) or 1 person in 400,000 (Moderna vaccine) had experienced a serious adverse allergic reaction.

In very rare cases, heart inflammation occurred after mRNA vaccination. Heart inflammation was observed in 1 person out of 200,000 to 6 persons out of 100,000, depending on the study. Young men were affected more frequently than average. Most of these heart inflammations were mild and could be treated well. However, a small proportion of the patients affected developed severe illnesses and, in individual cases, died. However, heart infections can also occur as a result of infections with Covid-19. According to the assessment of the Federal Commission for Vaccination, the risk of developing cardiac inflammation after a Covid-19 infection is higher than after an mRNA vaccination.