The side effects of the COVID-19 vaccine in children are similar to those in adults. They are generally mild to moderate and include soreness in the arm where the injection was given, redness and swelling, fatigue, headache, muscle and/or joint pain, chills, fever, swollen lymph nodes, nausea, and decreased appetite. In clinical trials, more children reported side effects after the second dose than after the first. Most side effects occurred within two days after vaccination and went away within one to two days.
Cases of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the heart’s outer lining) have been reported among adolescents and young adults who have received the Pfizer or Moderna vaccines. There were no cases of myocarditis or pericarditis among the 5- to 11-year-old study population. Reports of these conditions are rare, and the FDA and CDC have determined that the benefits of COVID-19 vaccination outweigh the known and potential risks of not being vaccinated. Learn more about these conditions.