- An allergic reaction, such as difficulty breathing, wheezing, hives, hoarseness, paleness, weakness, a fast heart rate, or dizziness.
- Behavior changes, such as passing out (losing consciousness), acting confused, being very sleepy or hard to wake up, or not responding to being touched or talked to.
- A seizure.
Call your doctor if:
- Redness and swelling at the site of the shot (injection) last longer than 48 hours.
- Your child is 3 months of age or younger and has a fever of 100.4°F (38°C) or higher.
- A fever lasts longer than 48 hours after receiving a shot.
- Any unusual reaction occurs.
If a fever develops after an immunization and you need to find out if you should call your doctor, see:
Talk with your doctor about whether you need special immunizations because you: