California Ban on Non-Medical Vaccine Exemptions Led to Coverage Spike in 'High-Risk' Counties

A California law stopping parents from citing religious or philosophical beliefs to opt out of vaccinating their children has improved rates of shots, a study has revealed.

In 2016, a ban on nonmedical exemptions from school entry requirements came into effect. To uncover what effect this had, a team of researchers examined county-level data on measles, mumps and rubella (MMR) vaccine coverage from 45 different state public health departments between 2011 and 2017, and from 17 states between 2010 and 2017.

After Senate Bill 277 was adopted, MMR coverage in California rose by 3.3 percent, nonmedical exemptions dropped by 2.4 percent, and medical exemptions went up by 0.4 percent during this period. Overall vaccination coverage rose by 4.3 percent, nonmedical exemptions by fell by 3.9 percent, and medical exemptions grew by 2.4 percent.

The data revealed changes in vaccination coverage across counties ranged from -6 to 26 percent, with the biggest spikes in "high-risk" counties where rates of shots were previously lower than the state average.

The researchers said the increase in medical exemptions was offset by the bigger reduction in nonmedical exemptions.

Vaccine hesitancy is a growing public health problem in the U.S., the authors said, one that has contributed to outbreaks of preventable diseases like measles.

Between January 1 to December 5, 2019, 1,276 cases of measles were confirmed across 31 states, according to the U.S. Centers for Disease Control and Prevention. That amounts to the biggest number of cases since 1992, and comes after the condition was declared eliminated in the U.S. in 2000 thanks to vaccine programs. More than three-quarters of cases were part of outbreaks in New York.

The outbreaks have in turn sparked debate over whether parents should be legally required to have their children undergo the procedure in order to protect others from the virus whose complications can be deadly in some cases.

Nathan Lo of the University of California, San Francisco, and colleagues wrote in the paper published in PLOS Medicine: "These study results support the idea that state-level governmental policies to remove non-medical exemptions can be effective strategies to increase vaccination coverage across the United States."

Back in September, the California Assembly passed legislation to prevent doctors from selling medical exemptions to the parents of school children who can no longer seek non-medical exemptions. Doctors who give out more than five will be reviewed by officials.

Senate Bill 276 will also require the California Department of Public Health to create a standardized form used by healthcare providers which would be sent to the California Immunization Registry, to document medical exemptions.

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A stock image shows a boy being vaccinated. Getty