November 30th, 2011

While vaccination rates in the U.S remain over 90%, there are pockets where those choosing not to vaccinate are causing some concerns.  In 8 different states, 1 in 20 children are not being vaccinated, reports the New York Times.

Health officials have not identified an exemption threshold that would likely lead to outbreaks. But they worry when some states have exemption rates climbing beyond 5 percent. The average state exemption rate has been estimated at less than half that.

Even more troubling are pockets in some states where exemption rates are much higher. In some rural counties in northeast Washington, for example, vaccination exemption rates in recent years have been above 20 percent and even as high as 50 percent.

“Vaccine refusers tend to cluster,” said Saad Omer, an Emory University epidemiologist who has done extensive research on the issue.