Child Vaccine Exemptions: States Getting Stricter?
Study finds bills to expand parental opt-outs are failing, while others to limit them have passed
Vaccine fears were set off in 1998, when a small study linked the measles-mumps-rubella vaccine to autism. That research was later found to be fraudulent, but some parents' worries over vaccine safety persist.
Despite that, lawmakers seem to be trying to rein in personal belief exemptions, Offit said.
That's at least partly in response to concerns about disease outbreaks. In 2010, for example, California had an outbreak of whooping cough that sickened more than 9,000 people and killed 10 infants -- most of whom were too young to be vaccinated.
In a recent study of that outbreak, researchers at Johns Hopkins University found that whooping cough cases tended to concentrate in areas of the state with the highest rates of personal belief exemptions.
For the new study, Omer's team looked at a legislative database maintained by the advocacy group Immunization Action Coalition.
The researchers found that between 2009 and 2012, 18 states introduced at least one bill on vaccine exemptions. Most of the bills -- 31 in all -- were aimed at launching or expanding personal belief exemptions. None of them passed.
There were only five bills intended to restrict the exemptions, but three of them were signed into law.
Omer and his colleagues emphasized that success rate. "All of the legislative efforts to expand exemptions failed," they said. "However, the majority of bills to restrict exemptions passed."
Offit agreed. "If three out of five passed, that's pretty good," he said.
And although there were many more bills trying to expand personal belief exemptions, Offit said he saw that as "a last flicker, because they all failed."
"Previous studies have shown that high vaccine refusal rates tend to increase the risk of vaccine-preventable disease in the whole community -- including for those who are vaccinated," Omer said. "So it is in everyone's interest to ensure that their community has high vaccination rates."