Can a Vaccine Give Me the Disease It’s Supposed to Protect Me Against?

Can a vaccine give me the disease it’s supposed to protect me against?

Paul Offit, MD: Hi, my name’s Paul Offit. I’m talking to you today from the Vaccine Education Center here at The Children’s Hospital of Philadelphia. I think one question sometimes that parents have is, “Is it possible that a vaccine could give you the disease that it’s trying to prevent?” And certainly for the vaccines where you take a virus and completely inactivate it, or you take just a part of a bacteria, the answer to that question is absolutely no.

So I think really where that question has relevance is for viral vaccines where what you do is you weaken the virus. You don’t kill it so that it can’t possibly reproduce itself, rather you weaken it so that it reproduces itself a little. So I think a parent can fairly ask, “Even though you’ve weakened it, isn’t it possible that the virus could be strong enough to cause the disease?”

And certainly it can’t do that for vaccine viruses like measles, or mumps, or German measles, which is rubella, or chickenpox. There was one, live, weakened viral vaccine that actually could cause the disease it was intended to prevent. That vaccine was the oral polio vaccine, otherwise known as Albert Sabin’s vaccine. We gave that vaccine in this country from the early 1960s up until the year 2000 and we stopped giving it in the United States. It could itself cause polio. The oral polio vaccine could itself cause polio in roughly 1 per 2.4 million doses.

That was a rare side effect, but it was real. And that’s why we stopped using that vaccine and went back essentially to Jonas Salk’s vaccine, which is the whole-killed polio virus vaccine.