Banning vaccine exemptions for philosophical or personal reasons increases rates by up to 26%

Legislation banning vaccine exemptions for philosophical or personal reasons increases childhood immunization rates by up to 26%, study finds

  • In 2016, California passed a law barring vaccine exemptions for philosophical or personal beliefs for children entering public schools
  • Rates of the MMR (measles, mumps, rubella) shot rose 3.3% state-wide
  • In high-risk counties that had low vaccine coverage, rates rose by up to 26%
  • Children with non-medical exemptions decreased by 2.4% across California

Banning non-medical exemptions drives up childhood vaccination rates, a new study finds.

Researchers looked at a 2016 California law that no longer allowed families to skip the protective shots for philosophical or personal reasons.

Statewide, rates of the MMR (measles, mumps, rubella) inoculation rose by 3.3 percent after the law went into effect.

In high-risk counties, where vaccine coverage was lowest, rates spiked by as much as 26 percent.

The team, from the University of California San Francisco, says the findings are evidence that such a law is successful, as several US state consider implementing their own strict vaccine requirements.

A new study from UC San Francisco has found that a law banning non-medical exemptions in the state caused MMR vaccine rates to increase by up to 26% (file image)

‘Vaccine hesitancy and the recent decline in vaccination rates is an increasing threat to public health and our patients,’ said senior author Dr Nathan Lo, a medical resident at UC San Francisco.

‘Our study shows that government policy has a role to address this, and that eliminating non-medical exemptions is an effective way of increasing vaccination coverage.’ 

Currently, 15 states allow non-medical exemptions for vaccines including ‘conscientious objector’ or ‘philosophical/personal beliefs.’

In 2016, California legislators passed a law eliminating non-medical exemptions for vaccines for children entering public schools.

For the study, published in PLOS Medicine, the team looked at how many children in California would have received the MMR vaccine if the law hadn’t gone into effect.

Researchers then compared the number to how many children actually did get immunized after the law passed.    

They found that rates of MMR vaccinations increased by 3.3 percent and by as much as 26 percent in some counties.

Children with non-medical exemptions decreased by 2.4 percent on a state-level and 4.3 percent across counties.

However, the number of children with medical exemptions increased by 0.4 percent. 

‘We did see an increase in medical exemptions, but in absolute terms the numbers remain small – one to two percent, driven largely by a few counties – and we can expect them to remain of similar magnitude in the near term,’ Dr Lo said. 

‘Overall vaccine coverage increased by 10 to 20 percent in the high-risk counties, far more than the increase in medical exemptions.’ 

Vaccination rates were up to 95 percent in almost all California counties, high enough coverage to create so-called ‘herd immunity. 

This occurs when the vast majority of a community – between 80 and 95 percent – becomes immune so that, if a disease is introduced, it is unable to spread.

Therefore, those who are unable to be vaccinated, including the ill, very young and very old, are protected.  

‘The implication of our study is the law brought about protection through herd immunity,’ said first author Hannah Karpel, a student at New York University School of Medicine. 

‘Even small average increases can have a big effect.’