Before their immune systems mature, young children are especially vulnerable to infections — and to falling far more ill than adults might with certain common illnesses.
That’s why childhood vaccination programs have been such a boon for public health. In the past 30 years, recommended childhood vaccines have prevented an estimated 1.1 million deaths and 32 million hospitalizations in the United States.
The recommended schedule for these vaccines is first set by an advisory committee to the Centers for Disease Control and Prevention, which reviews the recommendations and decides whether to adopt them. The committee’s members — which include experts in vaccination, infectious disease, pediatrics and public health — meet several times each year to review the latest clinical trials as well as health and safety data from the general population.
Today, children vaccinated in line with these recommendations are protected from 16 diseases, including infections that can cause paralysis, brain damage and deadly fevers. Those who aren’t given recommended shots or follow an alternative schedule — which research suggests is the case for an estimated 27 percent of U.S. children — may be at higher risk of developing these preventable illnesses.
“When we start spacing things out, the danger is that either the child gets exposed, or we never get them caught up and they miss out entirely,” said Dr. Beth Thielen, a pediatric infectious disease physician at the University of Minnesota.
Why is the vaccine schedule set the way it is?
To understand why doctors recommend vaccinating on a specific schedule, it’s helpful to understand what protection babies need and when. “We want them to have maximal protection when they need it, and when they need it is when they’re at the highest risk of serious infection and before they are exposed,” said Dr. Leila Posch, a pediatric infectious diseases physician at Children’s Hospital Los Angeles. “Second, we want to give vaccine doses when their immune system is mature enough to respond to them well.”