Addressing Parental Concerns About Vaccines

Nothing Is 100% Safe

“Vaccines are not 100% safe. Nothing is,” said Dr. Marshall. However, the risk of death due to vaccines is very small. In fact, no deaths due to vaccine adverse events occurred last year. You're more likely to die in an elevator accident or be struck by lightening.

“We need to be able to convince the public that the safety net that we have in this country is robust and it works.” The process starts with the well-regulated development of candidate vaccines and continues through clinical trials and Food and Drug Administration licensure. In addition, “we have committees of experts that review the data and decide who should get the vaccine and who shouldn't.” After that, vaccines are subject to adverse event scrutiny through the Vaccine Adverse Events Reporting System, the Vaccine Safety DataLink, and other organizations.

Heuristic Thinking Can Occur

Many people concerned about vaccines focus only on those with an exposure to vaccines who had a certain outcome (Guillain-Barré syndrome or febrile seizures, for example). They ignore the larger picture—those with an exposure who did not have a certain outcome, those with no exposure who did have a certain outcome, or those with no exposure and no outcome.

In addition, some parents demonstrate heuristic thinking when it comes to vaccines. In heuristic thinking, a known risk (the flu) is more acceptable than an unknown risk (an allergic reaction); a bad outcome is more tolerable if it occurs because of inaction than action; the probability that something will occur correlates with the ease with which we remember it or with the similarity of circumstances; rare risks are overestimated and common risks are underestimated. “Part of our challenge is to undo that kind of thinking,” said Dr. Marshall.

Many parents who are against childhood vaccinations think they can rely on herd immunity to protect their child. That is unfair to other parents and not necessarily a safeguard, he said. Unvaccinated children tend to live in clusters and spawn outbreaks, as in the case of a measles outbreak in March 2009 in California.

Vaccinology Isn't Understood

“People are confused about antigens. They see us, over the years, giving more and more vaccines, but what they don't understand is that the number of antigens that we're actually giving is much less,” Dr. Marshall said.

It's true that most pediatricians are not experts on vaccinology. “I don't think that all of us read all of the primary literature, but we do elect and appoint very smart people to our committees, who do look at every single piece of data and come up with recommendations,” he said. It is also true that natural immunity is better. “Natural chicken pox gives you more robust and longer-lasting immunity than the vaccine … but the cost of natural immunity is getting the disease. The cost of the vaccine is the very rare side effect.”

He reported that he has been a speaker and consultant for several pharmaceutical companies that make vaccines. Dr. Marshall has also received research grants from several pharmaceutical companies that make vaccines.