Abstract
This study evaluates the statewide change in medical exemptions in the first year under California Senate bill 277 and if medical exemptions increased in regions with high personal belief exemption use prior to its enactment.
California Senate bill (SB) 277 eliminated the personal belief exemption (PBE) provision from the state’s school-entry vaccine mandates prior to the 2016-2017 school year. Previously, vaccine-hesitant parents could acquire a PBE for their child based on philosophical or religious beliefs. Now, the only pathway for an unvaccinated kindergartener to enter a public or private school in California is with a medical exemption (ME), which requires a written statement from a licensed physician describing the medical reasons that immunization is unsafe. Previously, MEs were only granted to children with a contraindication to vaccination; however, SB 277 gave physicians broader discretion to grant MEs for reasons other than a contraindication, including family medical history.
One concern voiced after the passage of SB 277 was whether vaccine-hesitant parents would seek MEs as replacements for PBEs and would find physicians willing to oblige them. We evaluated the statewide change in MEs in the first year under SB 277 and whether MEs increased in regions with high PBE use prior to its enactment.
Methods
We used publicly available data from the California Department of Public Health’s yearly Kindergarten Immunization Assessment reports. Each year, all schools are required to submit kindergarten enrollment, vaccination, and exemption data; more than 95% of all kindergarteners are represented in the yearly reports, which include statewide and county-level data. We extracted the statewide ME and PBE percentages for incoming kindergarteners from 1996 to 2016. We calculated and mapped the 1-year change in ME percentage (2015 to 2016) for counties and used Pearson correlation to test whether county-level change in ME percentage was associated with PBE use in the year prior to the implementation of SB 277. We used ArcGIS (Esri), version 10.3, for mapping and R (R Foundation), version 3.3.2, for the correlation test.
Results
In the 20 years prior to SB 277, the percentage of kindergarteners with MEs was largely stable, whereas PBE use increased (Table). In the first year under SB 277, the ME percentage increased from 0.17% to 0.51%. The PBE percentage decreased from 2.37% in 2015 to 0.56% in 2016, as PBEs for children who entered multiyear transitional kindergarten programs prior to 2016 remained valid. The total exemption percentage (PBEs + MEs) decreased from 2.54% in 2015 to 1.06% in 2016.
Table. Enrollment and Immunization Exemptions Among California Kindergarteners, 1996-2016.
| Year | Enrollment | Medical Exemptions, No. (%) | Personal Belief Exemptions, No. (%) | Total Exemptions, No. (%) |
|---|---|---|---|---|
| 1996a | NA | NA (0.06) | NA (0.46) | NA (0.52) |
| 1997a | NA | NA (0.14) | NA (0.72) | NA (0.86) |
| 1998a | NA | NA (0.1) | NA (0.63) | NA (0.73) |
| 1999a | NA | NA (0.13) | NA (0.66) | NA (0.79) |
| 2000 | 526 466 | 584 (0.11) | 4032 (0.77) | 4616 (0.88) |
| 2001 | 523 516 | 710 (0.14) | 6225 (1.19) | 6935 (1.32) |
| 2002 | 519 397 | 784 (0.15) | 5742 (1.11) | 6526 (1.26) |
| 2003 | 513 519 | 693 (0.14) | 5938 (1.16) | 6631 (1.29) |
| 2004 | 510 074 | 747 (0.15) | 6340 (1.24) | 7087 (1.39) |
| 2005 | 512 733 | 778 (0.15) | 6794 (1.32) | 7572 (1.48) |
| 2006 | 503 160 | 827 (0.16) | 7108 (1.41) | 7935 (1.58) |
| 2007 | 499 301 | 889 (0.18) | 7811 (1.56) | 8700 (1.74) |
| 2008 | 501 046 | 928 (0.18) | 9529 (1.90) | 10 457 (2.09) |
| 2009 | 507 191 | 998 (0.20) | 10 280 (2.03) | 11 278 (2.22) |
| 2010 | 509 849 | 962 (0.19) | 11 868 (2.33) | 12 830 (2.52) |
| 2011 | 529 400 | 871 (0.16) | 12 665 (2.39) | 13 536 (2.56) |
| 2012 | 530 397 | 915 (0.17) | 14 791 (2.79) | 15 706 (2.96) |
| 2013 | 533 680 | 991 (0.19) | 16 817 (3.15) | 17 808 (3.34) |
| 2014 | 535 234 | 1034 (0.19) | 13 592 (2.54) | 14 626 (2.73) |
| 2015 | 551 123 | 931 (0.17) | 13 086 (2.37) | 14 017 (2.54) |
| 2016 | 562 924 | 2850 (0.51) | 3133 (0.56) | 5983 (1.06) |
Abbreviation: NA, not available.
The data from 1996 to 1999 were gathered from the 2002 report, which did not include the kindergarten enrollment or the raw number of medical exemptions and personal belief exemptions. The percentage values for these years are listed as presented in the report.
The 1-year change in county-level ME percentage ranged from −1.00% to 3.38% and was geographically variable across California (Figure). The county-level PBE percentage in 2015 ranged from 0% to 18.42%. We found a positive relationship between county-level change in ME percentage and previous PBE use (Pearson r = 0.65; P < .001; n = 56), signaling that counties with high PBE use prior to SB 277 had the largest increases in MEs after its implementation.
Figure. County-Level Change in the Percentage of Incoming Kindergarteners With a Medical Exemption From 2015 to 2016.
Two counties were not included in the analysis due to data censoring.
Discussion
The statewide increase in the number of children with MEs in 2016 and the county-level correlation with past PBE use suggest that some vaccine-hesitant parents may have successfully located physicians willing to exercise the broader discretion provided by SB 277 for granting MEs. If true, this practice would be inconsistent with the recommendation from the American Academy of Pediatrics to reserve MEs for children having contraindications. However, the study has limitations. Whether MEs were underused prior to 2016 (eg, children with contraindications having PBEs because they were easier to obtain) is unknown, as are the medical reasons for each ME.
Although the number of kindergarteners with any exemption decreased in the first year under SB 277, this outcome must be considered in context with the law’s grandfather clause, which permits all students with PBEs who entered kindergarten prior to 2016 to continue attending school until they reach seventh grade. The increase in the number of MEs granted in 2016 further weakens the immediate effect of SB 277 and may limit its long-term benefits if sustained. Moreover, because the largest increases in ME percentage occurred in regions with high past–PBE use, portions of California may remain susceptible to vaccine-preventable disease outbreaks in the near future. 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.
Section Editor: Jody W. Zylke, MD, Deputy Editor.
References
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