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. 2019 Jun;143(6):e20183301.
doi: 10.1542/peds.2018-3301. Epub 2019 May 21.

Elimination of Nonmedical Immunization Exemptions in California and School-Entry Vaccine Status

Paul L Delamater  1 , S Cassandra Pingali  2 , Alison M Buttenheim  3 , Daniel A Salmon  4 , Nicola P Klein  5 , Saad B Omer  6
Affiliations

Elimination of Nonmedical Immunization Exemptions in California and School-Entry Vaccine Status

Paul L Delamater et al. Pediatrics. 2019 Jun.

Abstract

Background and objectives: California implemented Senate Bill 277 (SB277) in 2016, becoming the first state in nearly 30 years to eliminate nonmedical exemptions from immunization requirements for schoolchildren. Our objectives were to determine (1) the impacts of SB277 on the percentage of kindergarteners entering school not up-to-date on vaccinations and (2) if geographic patterns of vaccine refusal persisted after the implementation of the new law.

Methods: At the state level, we analyzed the magnitude and composition of the population of kindergarteners not up-to-date on vaccinations before and after the implementation of SB277. We assessed correlations between previous geographic patterns of nonmedical exemptions and patterns of the remaining entry mechanisms for kindergarteners not up-to-date after the law's implementation.

Results: In the first year after SB277 was implemented, the percentage of kindergartners entering school not up-to-date on vaccinations decreased from 7.15% to 4.42%. The conditional entrance rate fell from 4.43% to 1.91%, accounting for much of this decrease. Other entry mechanisms for students not up-to-date, including medical exemptions and exemptions for independent study or homeschooled students, largely replaced the decrease in the personal belief exemption rate from 2.37% to 0.56%. In the second year, the percentage of kindergartners not up-to-date increased by 0.45%, despite additional reductions in conditional entrants and personal belief exemptions. The correlational analysis revealed that previous geographic patterns of vaccine refusal persisted after the law's implementation.

Conclusions: Although the percentage of incoming kindergarteners up-to-date on vaccinations in California increased after the implementation of SB277, we found evidence for a replacement effect.

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Conflict of interest statement

POTENTIAL CONFLICT OF INTEREST: Dr Salmon reports research and consulting support from Pfizer, Merck, and Walgreens; Dr Klein reports research support from Pfizer, Merck, GlaxoSmithKline, Sanofi Pasteur, Protein Science (now Sanofi Pasteur), Dynavax, and MedImmune; the other authors have indicated they have no potential conflicts of interest to disclose.

Figures

FIGURE 1
FIGURE 1
Composition of kindergarteners entering school who are not up-to-date on vaccinations. Percentages of students with a personal belief exemption (purple), medical exemption (green), and exempt (red), overdue (blue), and conditional entrance (tan) are provided for (A) all schools from 2000 to 2017 and for kindergarteners attending (B) public schools and (C) private schools from 2008 to 2017. Dashed lines are placed at the year before the implementation of AB2109 (2013) and SB277 (2015) and the statewide conditional entrance education- and enforcement-based effort (2014) to highlight the changes that occurred directly afterward.
FIGURE 2
FIGURE 2
Scatter plots and correlation results comparing pre- and post-SB277 entry mechanisms for kindergarteners who were not up-to-date. (A) Percentage of children who were up-to-date in 2017 and 2015 with a 1:1 line for reference. Pearson’s correlations (R and P values) for the personal belief exemption rate (2015) and (B) the not–up-to-date rate (2017), (C) the combined replacement mechanism (medical exemptions and exempt) rate (2017), (D) the medical exemption rate (2017), (E) the exempt rate (2017), and (F) the conditional entrance rate (2017) are shown.
FIGURE 3
FIGURE 3
The personal belief exemption rate in 2015 and the combined replacement mechanism rate in 2017.
See this image and copyright information in PMC

References

    1. Centers for Disease Control and Prevention (CDC) Ten great public health achievements–worldwide, 2001-2010. MMWR Morb Mortal Wkly Rep. 2011;60(24):814–818 - PubMed
    1. Atwell JE, Van Otterloo J, Zipprich J, et al. . Nonmedical vaccine exemptions and pertussis in California, 2010. Pediatrics. 2013;132(4):624–630 - PubMed
    1. Omer SB, Salmon DA, Orenstein WA, deHart MP, Halsey N. Vaccine refusal, mandatory immunization, and the risks of vaccine-preventable diseases. N Engl J Med. 2009;360(19):1981–1988 - PubMed
    1. Orenstein WA, Hinman AR. The immunization system in the United States - the role of school immunization laws. Vaccine. 1999;17(suppl 3):S19–S24 - PubMed
    1. Shaw J, Mader EM, Bennett BE, Vernyi-Kellogg OK, Yang YT, Morley CP. Immunization mandates, vaccination coverage, and exemption rates in the United States. Open Forum Infect Dis. 2018;5(6):ofy130. - PMC - PubMed

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