How Vaccines Strengthen Your Baby’s Immune System

Although children continue to get several vaccines up to their second birthday and sometimes, several in one office visit, these vaccines do not overload the immune system.

Baby flexing his muscles.

Your child is exposed to thousands of germs every day in his environment. This happens through the food he eats, air he breathes, and things he puts in his mouth.


Babies are born with immune systems that can fight most germs, but there are some deadly diseases they can’t handle. That’s why they need vaccines to strengthen their immune system.


Vaccines use very small amounts of antigens to help your child’s immune system recognize and learn to fight serious diseases. Antigens are parts of germs that cause the body’s immune system to go to work.

How Vaccines Strengthen Your Baby’s Immune System.

Thirty years ago, vaccines used 3,000 antigens to protect against 8 diseases by age two. Today, vaccines use 305 antigens to protect against 14 diseases by age two.

Thanks to scientific advances, today’s vaccines can protect children from more diseases using fewer antigens. Vaccines contain only a tiny fraction of the antigens that babies encounter in their environment every day.

Vaccines and your baby's immune system.

How do vaccines help babies fight infections?
Join baby Jack and his #parents as they find out how #vaccines help train your baby’s immune system to help prevent disease.

Page last reviewed: August 5, 2019