Fevers After Vaccines

It is not uncommon to have a local reaction at the injection site or to have a fever following a vaccine.

Injection sites may have tenderness, redness and swelling within 24 hours of the vaccine and it may take 3-5 days to resolve.

If fever occurs following vaccination it typically begins within 12-24 hours and may last 1-2 days. However following a MMR or Varicella vaccine the fever may occur 1 week or more later. Fevers are a normal part of immune responses thus fever following vaccination offers evidence that the child’s immune system is responding to the vaccine and building immunity against the targeted virus or bacteria.

A local reaction or fever can be treated with a non-aspirin pain reliever like acetaminophen (ex: Tylenol) or ibuprofen (ex: Motrin) to help your child feel better. However, it is not recommended to give a pain reliever prior to vaccination.

Call our office if you see:

  • Fever lasting more than 3 days.
  • Fever is greater than 104.
  • Redness around an injection site is becoming larger and more painful after 3 days.
  • Nonstop crying for more than 3 hours.
  • Your child looks or acts very sick to you or you have additional concerns.