Side effects from the vaccines are similar to those children may have after getting other routine vaccinations. These tend to be mild and temporary. And some children have no side effects.
According to the CDC, for children 4 years of age and older, the side effects are more common after the second dose. Side effects can include pain, redness or swelling in the arm where the vaccine was received, fever, tiredness, headache, muscle or joint pain, and swollen lymph glands. In children 3 years of age or younger, side effects can include pain at the vaccine site, swollen lymph nodes, irritability or crying, sleepiness, and loss of appetite. Some children had milder side effects after receiving the Pfizer-BioNTech vaccine.
Parents or guardians should contact their child’s health care provider if they have questions about managing side effects or using non-aspirin pain relievers. Do not give aspirin to children younger than 18. More information is available on the CDC website.