A mild illness is usually not a reason to delay vaccinations. Your doctor can help you decide which vaccines your child can still receive safely.

It’s tempting to cancel or reschedule a doctor’s appointment for vaccines when your child has the sniffles, an upset stomach, or a mild fever. But doctors at leading health organizations, like the Centers for Disease Control and Prevention, the American Academy of Family Physicians, and the American Academy of Pediatrics say mild illness usually is not a reason to put off vaccinations.

Your child may still be vaccinated if he or she has:

  • A low-grade fever (less than 101 degrees)
  • A cold, runny nose, or cough
  • Ear infection
  • Mild diarrhea

There is no health benefit to waiting to vaccinate your child if he or she has a mild illness. It’s important that children get their vaccines on time—even if they don’t feel well—so they’re protected against serious diseases.

It is not recommended to give your child pain or fever reducers before vaccination, but it is okay to give a non-aspirin pain reliever after the appointment as long as your doctor approves. Giving these medications before vaccination can interfere with the immune response.

Vaccines do not make a mild illness worse. A child’s immune system can respond to millions of antigens every day. Antigens are things like bacteria and viruses that cause your child’s body to produce antibodies against them. Vaccines have only a tiny fraction of the antigens that children encounter on a daily basis. So, the immune system can handle getting vaccines to build immunity to diseases and fight minor illnesses at the same time.

Vaccines do not make symptoms of illness worse—though they may cause mild side effects, like a mild fever or soreness or swelling where the shot was given. To help with discomfort from these side effects, put a cool, wet washcloth on the sore area or ask your child’s doctor about using pain- or fever-reducing medicine.

Mild illness also does not affect how well the body responds to a vaccine. Vaccines build up protection in a child who is mildly ill as well as they do when the child is healthy.

Your child may not receive some vaccines if he or she has:

  • A chronic health condition (for example, cancer)
  • A weakened immune system (for example, if undergoing chemotherapy or is on certain medications after a transplant)
  • A previous allergic reaction to a vaccine

Reactions to a vaccine, such as fever, could make it harder to diagnose and treat a serious illness. And it’s possible that signs of the illness could be mistaken for a reaction to the vaccine.

If your child has a serious illness or medical condition, talk to your child’s health care provider.

Source: CDC: Vaccines When Your Child is Sick