More parents sought medical exemptions for immunizations for incoming kindergartners in the year since California eliminated the personal-belief exemption -- but overall, fewer people are opting out, according to a new study.
The results published this week in the Journal of the American Medical Association hint that some parents who don't want to vaccinate their children may have found doctors willing to give medical exemptions to students, the Los Angeles Times said. It's a potential trend that may undercut the collective protection against contagious diseases that the state law sought to bolster.
When students enroll in school, they're required to show proof that they were vaccinated against diseases such as polio, chickenpox and measles -- infections that can spread quickly through an unprotected group. Students can be exempted from the vaccine requirement if they have a medical condition that makes immunizations dangerous, such as pediatric cancer or HIV. In most states, parents also can get exemptions based on personal beliefs, the newspaper said.
State Senate Bill 277, passed in 2015, did away with those personal-belief exemptions in California. The legislation was prompted by a measles outbreak that originated at Disneyland in 2014 and wound up infecting 159 people. That outbreak was likely exacerbated by low vaccination rates, an earlier analysis found.
California's law sought to raise vaccination rates and improve herd immunity, the collective protection provided when an overwhelming majority of people in a group are immune to a disease. Herd immunity helps protect those who, because of medical reasons, cannot be vaccinated and are vulnerable to infections.
But the state law also widened the definition of a medical exemption, allowing doctors to take into account such factors as family medical history.
From 2015 to 2016, the medical exemption rate jumped from 0.17 percent to 0.51 percent -- a threefold increase.
The personal-belief exemption rate, by comparison, rose from 1.32 percent in 2005 to 2.37 percent in 2015, then fell to 0.56 percent in 2016, after the bill's passage. The rate didn't fall to zero largely because of children in multiyear transitional kindergarten programs who'd received personal-belief exemptions before 2016, according to the Times.
Researchers found the total exemption rate dropped from about 2.5 percent to just over 1 percent. That's good news for the law, said Paul Delamater, a health geographer at the University of North Carolina at Chapel Hill and lead author of the new report.