The U.S. FDA authorized the Moderna pediatric vaccine for children 6 months to 5 years old under an Emergency Use Authorization (EUA), meaning the vaccine was proven safe and effective for this age group. In clinical trial participants, the most commonly reported side effects included pain, redness and swelling at the injection site, fever and underarm swelling/tenderness of lymph nodes in the same arm as the injection. When the vaccine was administered in the thigh instead of the arm, some patients experience groin swelling/tenderness of lymph nodes in the same thigh as the injection.  

Learn more about COVID-19 vaccine side effects in children and teens.