Measles outbreaks underscore need for vaccination

With the number of measles cases in the United States hitting a 20-year high, pediatric infectious disease specialist Christina Hermos, MD, is frustrated by the "anti-science" movement against vaccination that underlies the nationwide outbreak.

"There is a lot of misinformation, myths and, frankly, lies in the lay media about dangers associated with vaccines that are basically not true," said Dr. Hermos, assistant professor of pediatrics. "We know that vaccines are extremely safe and extremely effective."

As of June 6, the U.S. Centers for Disease Control had received reports of 397 measles cases in 20 states. According to the agency, nearly all of the outbreaks involved unvaccinated people who brought measles back after a trip overseas.

"Right now we're seeing the highest number of measles cases since 1994," said Hermos. "The primary cause is imported cases then spreading among communities where the children are unvaccinated or under-vaccinated."

Vaccine refusal explains why children have been sickened, but what about adults who have contracted measles despite being previously vaccinated?

"We know that the vaccine is 98 to 99 percent effective, so it could be a rare few who didn't respond to the vaccine or whose immunity waned," Hermos explained. "About 69 percent [of reported cases of measles] are in the unvaccinated, and 20 percent more [whose vaccination status is] unknown, which accounts for almost everyone."

In Massachusetts, which boasts high childhood vaccination rates, only eight cases of measles have been reported this year; Hermos and colleagues have not seen any at Worcester's UMass Memorial Medical Center.