Why Do Kids Get So Many Vaccines at Once?

Why do kids get so many vaccines at once?

Speaker 1: Why do kids get so many vaccines at once?

Paul Offit, MD: It's a fair question. I mean, it's really hard to watch your child get laid down on that crinkly white paper and get four or five shots at one time.

So generally, children in the first few years of life will get vaccines to prevent 14 different diseases. It makes it much easier for the child if you can give vaccines at the same time rather than having them come much more frequently during those first few years.

Now, vaccines are not allowed to be given at the same time until you prove that when you give a vaccine, or you add a vaccine to the schedule, that it doesn't interfere with the safety profile or the immunogenicity profile of existing vaccines and vice versa, that those vaccines don't interfere with the safety or immunogenicity profile of the vaccine that you're giving. So, those are called concomitant use studies. There are hundreds and hundreds of them. No vaccine can get onto the schedule until you show that.

Now, the reason children are given so many vaccines is that all of those vaccines prevent disease that can cause children to suffer, be hospitalized, cause permanent harm or, occasionally, die. So that's why we give the vaccines that we give. And by sort of grouping vaccines, it makes it much easier for the child.

There was a study that was done trying to answer the question, how stressed are children when they get vaccines? And the way that that physiologists measure stress is that they look at the levels of something called cortisol. So, if you give a child say a dose one vaccine, you can measure the cortisol level and then see what happens if you give them instead of just one shot at the time, you give them two shots or three shots or four shots or five shots.

And what they found, interestingly, was that as you gave more shots that actually didn't increase the cortisol level, or said another way, you were basically maximally stressed out at one shot. So, if that's true, it makes sense then actually to give as many as you can at that one visit rather than to space them out, at which point you're just gonna have more and more times during which children are going to be stressed rather than fewer times.

So, that's why those studies are done the way they were done, and that's why children get vaccines in the manner in which they get them.