Paul A. Offit, MD, discusses the immunological components in vaccines and how their numbers (160 for all 14 childhood vaccines combined) are negligible as compared to the trillions of bacteria living on the surface of our bodies, to which we develop an immune response.
Do babies get too many vaccines?
Paul Offit, MD: Hi, my name is Paul Offit, and I’m talking to you today from the Vaccine Education Center here at Children’s Hospital of Philadelphia. I think one question that parents have that seems to be their most common concern about vaccines is, “Are children just getting too many vaccines too soon?” It’s a reasonable question to ask. I mean any reasonable parent who sees their child get as many as 26 inoculations in the first few years of life, as many as five shots at one time, I think can reasonably fear it’s just too much.
But it’s really not the number of shots, or number of vaccines the children get. It’s really the number of immunological components in the vaccine that matters. So by immunological component, what I mean is a bacterial protein, or a viral protein, or this sort of complex sugar coating that sits on the surface of the bacteria called polysaccharide. Those are the immunological components of vaccines.
And if you add them all up, all those 14 different vaccines the kids get in the first few years of life, it adds up to about a 160 immunological components. Now that may seem like a lot. But when you think about what children encounter typically and manage every day, it’s really not just figuratively, but literally, a drop in the ocean.
So here’s what I mean. When you’re in the womb, you’re in a sterile environment. When you enter the birth canal and the world, you’re not. And very quickly, you have living on the surface of your body, trillions of bacteria, literally trillions of bacteria. You have about a 100 trillion bacteria on the surface of your body — that’s 10 times more than you have cells in your body — to which you make an immune response. You make an immune response to those bacteria. I mean children and adults make grams of immunoglobulins, like immunoglobulin G, or secretory immunoglobulin A every day. Because they want those bacteria to stay at mucosal surfaces and not invade.
Now each bacterium, single bacterium, contains between 2,000 and 6,000 immunological components. And remember, I said the total number of immunological components in vaccines is only about 160. Frankly I think that a common cold infection is a far greater immunological challenge than all of the vaccines that children get combined.
Related Centers and Programs: Vaccine Education Center
Last Reviewed on Apr 20, 2015