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Why Immunize Your Child

Why does my child need to be immunized?

Immunizations have helped children stay healthy for more than 50 years. They are safe and they work. In fact, serious side effects are no more common than those from other types of medication such as antibiotics and fever reducers and pain relievers.

Vaccinations have reduced the number of infections from vaccine-preventable diseases by more than 90%! Yet many parents still question their safety because of misinformation they’ve received. That’s why it’s important to turn to a reliable and trusted source, including your child's doctor, for information.

The following are answers to common questions parents have about immunizations.

Q: "Why are some of these vaccines still needed if the diseases are not as common anymore?"

A: These diseases are less common in large part due to vaccines. If vaccines were not given, the bacteria and viruses that cause these diseases could begin to infect more and more children again. 

For example, before the Hib vaccine was developed in the 1980s, there were about 20,000 cases of Hib disease in the United States a year.

Today there are fewer than 100 cases a year. However, the bacteria that causes Hib disease still exists. That is why children
need the vaccine to be protected.

In the United States vaccines protect children from many diseases. However, in many parts of the world vaccine- preventable diseases are still common. Because diseases may be brought into the United States by Americans who travel abroad or from people visiting areas with current disease outbreaks, it’s important that your child is vaccinated.

Q: "Do vaccines even work? It seems like most of the people who get these diseases have been vaccinated."

A: Yes. Vaccines work very well. Millions of children have been protected against serious illnesses because they were immunized. Most childhood vaccines are 90% to 99% effective in preventing disease. When a large majority of children have been vaccinated, it is expected that most who get the disease will have been vaccinated. And if a vaccinated child does get the disease, the symptoms are usually milder with less serious side effects or complications than in a child who hasn’t been vaccinated.

Q: "What side effects will my child have after getting a vaccine? Are they serious?"

A: There may be mild side effects, like swelling, redness, and tenderness where the shot was given, but they do not last long. Your child may also have a slight fever and be fussy for a short time afterward. It is rare for side effects to be serious. However, call your child's doctor right away if your child has

  • A very high fever (>103°F) and is younger than 3 months
  • Hives or black-and-blue areas at places where the injection was not given
  • A seizure

You should also call your child's doctor if you have any other concerns.


Q: "Should some children not be immunized?"

A: Children with certain health problems may need to avoid some vaccines or get them later. In most cases, children with cancer, those taking oral or injected steroids for lung or kidney conditions, or those who have problems with their immune systems should not get vaccines that are made with live viruses. To protect these children it is very important for others to be vaccinated. For children with a recent history of nerve disorders, the pertussis part of the DTaP vaccine may need to be delayed. However, a child with a minor illness such as low-grade fever (<100.4°F), an ear infection, cough, a runny nose, or mild diarrhea can safely be immunized.

Last Updated
Adapted from Immunizations & Infectious Diseases: An Informed Parent's Guide (Copyright © 2006 American Academy of Pediatrics)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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