How to handle questions about vaccine safety



SAN DIEGO – Parental concerns about vaccine safety are a reality of pediatric practice. False perceptions that vaccines are dangerous or unnecessary have eroded herd immunity to the extent that almost 600 measles cases have been reported thus far in 2014 – an unprecedented number, Dr. Paul Offit said at the annual meeting of the American Academy of Pediatrics.

Dr. Offit recommended strategies for handling some of the most common questions and concerns parents raise about vaccine safety. He is director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, and is the Maurice R. Hilleman Professor of Vaccinology and professor of pediatrics at the University of Pennsylvania, also in Philadelphia.

Dr. Paul A. Offit

Dr. Paul A. Offit

Parents may ask: How do you know vaccines are safe? I researched them on the Internet and learned they’re not.

“When people say they’ve done their research on a vaccine and have decided not to get it, what they really mean is they’ve read other people’s opinions on the Internet,” Dr. Offit said. Parents need to understand that not all information sources are equivalent, and that a vaccine must undergo extensive testing before the Food and Drug Administration licenses it or the American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend it, he said. “The phase III trials invariably involve thousands of children,” he added.

But the package insert for the vaccine lists a lot of adverse events.

Any adverse event reported before the vaccine is licensed will be listed on the package insert, whether or not the vaccine caused the event, Dr. Offit said. For example, the original package insert for the chicken pox (varicella) vaccine listed fractured leg as an adverse event, because one recipient of the varicella vaccine broke his or her leg within 42 days after receiving the vaccine, he said. “Package inserts are not a medical communication document,” he added. “They are a legal communication document.”

Why are people being compensated for vaccine harm if it isn’t a problem?

The question refers to the National Vaccine Injury Compensation Program, which has paid more than $2.8 billion in compensation awards to petitioners since 1989. The program is “a large and tempting pool of money for personal injury lawyers to file compensatory injury suits on behalf of their clients,” Dr. Offit said. But just because a court awarded damages for harm does not mean the vaccine actually caused harm, he said. “The courts are never a place to determine scientific truths. The place you do that is in the scientific venue, by studies.”

Vaccines can contain potential allergens, primarily gelatin (a stabilizer) and latex (in vials or syringes that contain natural rubber), Dr. Offit noted. However, the rate of truly severe reactions to vaccines is extremely low – about one case per 1-2 million doses of vaccine, he said. An exception is yellow fever vaccine , which has caused fatal anaphylaxis, and oral polio vaccine also “had the potential to revert to wild type, which is why we went to the fully inactivated polio vaccine by the year 2000,” Dr. Offit noted. Thrombocytopenia is a potential adverse reaction of some vaccines, but is rare, and there are no compelling data associating measles vaccine with encephalopathy, he said.

The fact of the matter is that vaccines are a product of pharmaceutical companies. Why should I trust a product that is from a pharmaceutical company?

“The fact is you don’t have to trust pharmaceutical companies,” Dr. Offit said. “A reporting system for adverse events is out there – VAERS [Vaccine Adverse Event Reporting System]. The vaccination safety data will show whether or not there is a safety issue.”

As an example, the human papillomavirus (HPV) 4 vaccine was studied in millions of children after it was licensed in the United States, Dr. Offit said. “The only symptom found was fainting,” he emphasized.

“It’s also not good business to make a vaccine that will do harm,” Dr. Offit said, adding that prelicensure studies of vaccines have cost up to $600 million.

I heard that if I am pregnant, I should not get the flu vaccine because it contains mercury, which is neurotoxic and can harm my baby.

Parents can benefit from understanding the difference between methylmercury – which naturally occurs in the environment and is neurotoxic at high levels of exposure – and ethylmercury, which is formed when the body breaks down the thimerosal that is found in small amounts in some vaccines, Dr. Offit said. Ethylmercury poses much less risk to humans than methylmercury, because it is excreted from the body about 10 times faster, he added.


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