Physicians May Be Helping Parents Avoid Kids' Vaccines

Norra MacReady

September 06, 2017

California parents who do not want to vaccinate their children may be getting help from some sympathetic physicians, according to the findings of a new study.

After the 2014 to 2015 measles outbreak linked to Disneyland in Orange County, California, the California state legislature passed Senate Bill (SB) 277, which eliminated personal belief exemptions (PBEs) for mandatory childhood vaccinations. However, SB 277, which took effect with the 2016 to 2017 school year, gives physicians more latitude for granting medical exemptions from vaccination.

In a survey of children enrolling in kindergarten for the 2016 to 2017 school year, the percentage of those with medical exemptions (MEs) excusing them from mandatory vaccinations tripled from the year before, whereas the percentage of students with PBEs declined by more than 75%, Paul L. Delamater, PhD, and colleagues write in an article published in the September 5 issue of JAMA.

When they analyzed the data by individual counties, the authors found a positive relationship between the increase in MEs and previous percentage of PBEs, "signaling that counties with high PBE use prior to SB 277 had the largest increases in MEs after its implementation."

The results suggest that "some vaccine-hesitant parents may have successfully located physicians willing to exercise the broader discretion provided by SB 277 for granting MEs," Dr Delamater, from the Department of Geography at the University of North Carolina at Chapel Hill, and coauthors write.

The findings also raise the concern that areas with high rates of vaccine exemptions "may remain susceptible to vaccine-preventable disease outbreaks in the near future," they warn. "Although this study was limited to a single year of data following the implementation of SB 277, the results warrant attention from both the medical and public health communities."

Dr Delamater and colleagues analyzed data from the Kindergarten Immunization Assessment reports, which are published annually by the California Department of Public Health and include information on more than 95% of kindergarteners across the state. In the 16 years before passage of SB 277, the percentage of children entering school with MEs ranged from about 0.11% to 0.20%. In 2016, the first year that SB 277 went into effect, the figure jumped to 0.51%.

Meanwhile, during the same period, the percentage of children with PBEs increased steadily from 0.77% in 2000 to 2.37% in 2015, and then dropped to 0.56% in 2016 as SB 277 took effect.

"The total exemption percentage (PBEs + MEs) decreased from 2.54% in 2015 to 1.06% in 2016," the authors write.

In a county-level analysis, the changes in MEs from 2015 to 2016 ranged from −1.00% to 3.38%, with a positive relationship between changes in percentages of ME by county and previous use of PBEs in those same counties (Pearson r, 0.65; P < .001; n = 56).

Study limitations include use of only 1 year's worth of data and the possibility that MEs were underused before implementation of SB277, because until 2016, PBEs were easier to obtain.

The authors note that SB 277 also allows PBEs for children who entered kindergarten before 2016 to remain in effect until those children enter seventh grade. That, plus the increase in MEs obtained in 2016, "further weakens the immediate effect of SB 277 and may limit its long-term benefits if sustained," the authors point out.

The authors have disclosed no relevant financial relationships.

JAMA. 2017;318:863-864. Abstract

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