It’s common for children to have mild reactions after a vaccine, since some soreness or a low fever can be part of the body building immunity. Knowing what to expect and when a reaction warrants a call to the doctor can make the aftermath of a shot easier to manage.
Common Reactions
Pain, swelling, or redness at the injection site are common, along with fever, fussiness, tiredness, or a reduced appetite. These reactions tend to reflect the immune system responding as expected and usually resolve within a few days.
Easing Soreness at the Injection Site
A cool, damp cloth applied to the area can help reduce redness and swelling. Letting the child rest the arm or leg rather than using it strenuously for a bit is also commonly suggested.
Managing a Low Fever
Offering fluids more often and dressing the child in light clothing can help with a low fever after a shot. Keeping the room at a comfortable, cool temperature is another commonly recommended step. If the fever is high enough to make the child noticeably uncomfortable, checking the age-appropriate dosing on a fever reducer with a pharmacist or the pediatric office can help before giving any medicine.
When to Call a Doctor Right Away
A fever of 104°F (40°C) or higher, hives or a rash spreading across the body, or swelling of the face, lips, or hands can point to a more serious reaction and call for prompt medical attention. Unusual limpness or difficulty breathing are also signs that shouldn’t wait for a regular appointment. This information is based on U.S. (CDC) guidance; if you live elsewhere, check with a local pediatric provider for country-specific recommendations. This information isn’t a diagnostic tool and doesn’t replace advice from a medical professional.