California immunization rates hit new highs after state law limits parental exemptions

The vaccination rate among kindergardeners increased in California after a tougher law came into effect.

A tougher vaccine law in California that prohibits parents from using personal beliefs to exempt their kids boosted coverage rates significantly in the first school year after its implementation.

California's rate of all-vaccinated kindergarteners grew to 95.6% for the current school year, the first under a new, more restrictive law, the California Department of Public Health reported (PDF). That's up from 92.8% the previous year—and the highest rate the agency has recorded since the 2001-02 school year, when the current vaccine schedule went into effect.

The increase is particularly notable in measles. More than 97% of the state’s kindergartners received both shots of the MMR vaccine, up from last year’s 94.5%. The number of counties reporting two-dose rates lower than the 95% threshold decreased to 14—less than one-quarter of the state's counties—from 31 (53%) in the previous school year.

California vaccination rate
Immunization rates among kindergarten students in California.
Chart: California Department of Public Health
California's new law might not be the only thing fueling measles vaccination increases. Around 2013, the state's measles vaccination rate, similar to patterns with several other shots, hit a record low of slightly above 92%. Then came the measles outbreak at Disneyland in December 2014, which sickened 131 people in California and spread to at least seven other states and two more countries.

Since then, vaccination rates have been steadily bouncing back. And CDPH acknowledges that the improvement might be “attributable to an increased awareness of the risks of vaccine-preventable diseases and benefits of immunization” stemming from that outbreak.

Back in 2015, California lawmakers passed SB 277, which no longer allows personal or religious exemptions for kids entering kindergarten and seventh grade. The law ran into opposition, with hundreds of protesters taking to the state capitol.

Undeterred, state officials implemented the law, citing public health concerns.

SB 277 doesn’t regulate children who’ve already passed those grade levels, or those who are home schooled, but state Sen. Richard Pan, a pediatrician, applauded the improvement. “We halted the bleeding,” he said, as quoted by Los Angeles Times.

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California's vaccination coverage increase comes at a time when antivaccine sentiments appear to be gaining steam around the country, partly because of the seemingly skeptical stance held by President Donald Trump. On a number of occasions, Trump has talked up the long-debunked theory of a link between vaccines and autism.

Late last month, about 150 parents gathered in Washington, D.C., petitioning for a change to the country’s mandatory vaccination policies.