Changes in California vaccine exemption laws projected to have limited effect on increasing childhood vaccination rates

A study found that laws developed in California to decrease the number of children who are exempt from receiving vaccines may have little effect. This is because parents motivated by a hesitancy to vaccinate continue to find alternate pathways around the laws. Findings from the brief research report are published in Annals of Internal Medicine.

In 2015, California passed Senate Bill 277 (SB277), which banned nonmedical exemptions from school-entry vaccine mandates. However, in the first 3 years after SB277 was passed, rates of both medical exemptions and students who were exempt from requirements and not up to date on vaccination increased. In response, California passed Senate Bill 276 (SB276) in 2019, adding additional scrutiny to medical exemptions.

Led by a researcher at the University of North Carolina at Chapel Hill, a group of scholars studied publicly available data on vaccination and school enrollment to estimate the percentage of California schoolchildren with an exemption from vaccination from 2015 to 2027 under three different scenarios: 1) current exemption use continues (no SB276); 2) the potential effect of SB276; or 3) a hypothetical scenario in which neither SB277 or SB276 was implemented (for comparison).

The researchers estimate that a large percentage of California schoolchildren will continue to be exempted from vaccination, even after the passage of the new laws. These findings demonstrate how the persistence of vaccine hesitancy and alternate pathways to avoid vaccination may mitigate the effects of efforts to increase vaccination coverage in schools.