It is normal to have mild fever or swelling after getting a vaccine.

fact_checkWhat experts say

• infoLike any medicine, a vaccine can cause side effects, but these are usually very minor and last only a short time, such as a sore arm or a mild fever.1
• infoSoreness, redness and swelling where the vaccine is given, along with fever, muscle aches and headache, can happen after vaccination.2
• infoMore serious side effects are possible but extremely rare.12
• infoA health problem that shows up after a vaccine is not always caused by the vaccine; only in extremely rare cases is the vaccine found to be the cause.1
• infoA person is far more likely to be badly harmed by a disease than by a vaccine; diseases like measles, meningitis, hepatitis B and polio can be deadly or cause lasting disability.1

checklistWhat to do

• check_circleIf you or your child has a reaction you did not expect after a vaccine, talk to your health worker or doctor.1
• check_circleTell your doctor if you feel dizzy, if your eyesight changes, or if you hear ringing in your ears after a vaccine.2
• check_circleGetting the recommended vaccines protects you and your child from diseases that can be deadly or cause lasting disability.1

menu_bookSources

1. 1Vaccines and immunization: Vaccine safetywho.intopen_in_new
2. 2Possible Side Effects from Vaccinescdc.govopen_in_new

Updated 28 Sep 2026