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. 2013 Jun 24;31(29):3009-13.
doi: 10.1016/j.vaccine.2013.04.053. Epub 2013 May 10.

Nonmedical exemptions to immunization requirements in California: a 16-year longitudinal analysis of trends and associated community factors

Jennifer L Richards  1 , Bradley H Wagenaar, Joshua Van Otterloo, Rahul Gondalia, Jessica E Atwell, David G Kleinbaum, Daniel A Salmon, Saad B Omer
Affiliations

Nonmedical exemptions to immunization requirements in California: a 16-year longitudinal analysis of trends and associated community factors

Jennifer L Richards et al. Vaccine. .

Abstract

Background: Rates of nonmedical exemptions to kindergarten-entry immunization requirements have increased over the past 2 decades, especially in states that permit philosophical exemptions and/or have easier administrative policies for obtaining nonmedical exemptions. We evaluated trends in school personal belief exemption rates over the period 1994-2009 in California, and associated school and community characteristics.

Methods: We used data on personal belief exemptions from 6392 public and private elementary schools from the California Department of Public Health, as well as census tract and school demographic data. Generalized estimating equations were used to model annual mean increases in personal belief exemption rates, and to identify school and community characteristics associated with personal belief exemption rates.

Results: Over the study period, the average school personal belief exemption rate increased from 0.6% in 1994 to 2.3% in 2009, an average of 9.2% (95% CI: 8.8-9.6%) per year. The average personal belief exemption rate among private schools over the entire study period was 1.77 (95% CI: 1.55-2.01) times that among public schools. The annual rate of increase was slightly higher among private schools (10.1%, 95% CI: 9.1-11.1%) than among public schools (8.8%, 95% CI: 8.4-9.2%). Schools located within census tracts classified as rural had 1.66 (95% CI: 1.26-2.08) times higher personal belief exemption rates than schools located within urban census tracts. Exemption rates were also associated with race, population density, education, and income.

Conclusions: This study confirms concerns about increasing rates of nonmedical exemptions to kindergarten vaccine requirements within the state of California, using data collected over a 16-year period.

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Conflict of interest statement

Conflict of interest

Saad B. Omer was awarded the Maurice R. Hilleman Early-stage Career Investigator Award by the National Foundation for Infectious Diseases in 2009. The award was funded by an unrestricted educational grant to the National Foundation for Infectious Diseases from Merck and Co., Inc. However, he had no direct interaction with Merck.

No other authors report any conflict of interest.

Figures

Fig. 1
Fig. 1
Average school personal belief exemption rates overall and by school type, 1994–2009.
See this image and copyright information in PMC

References

    1. Omer SB, Pan WK, Halsey NA, Stokley S, Moulton LH, Navar AM, et al. Nonmedical exemptions to school immunization requirements: secular trends and association of state policies with pertussis incidence. JAMA. 2006;296(14):1757–63. - PubMed
    1. U.S. Centers for Disease Control and Prevention. Vaccination coverage and surveillance: annual school assessment reports. http://www.cdc.gov/vaccines/stats-surv/schoolsurv/assessment-reports.htm. [accessed 16.04.12]
    1. Omer SB, Richards JL, Ward M, Bednarczyk RA. Vaccination policies and rates of exemption from immunization, 2005–2011. NEJM. 2012;367(12):1170–1. - PMC - PubMed
    1. Rota JS, Salmon DA, Rodewald LE, Chen RT, Hibbs BF, Gangarosa EJ. Processes for obtaining nonmedical exemptions to state immunization laws. Am J Public Health. 2001 Apr 4;91:645–8. - PMC - PubMed
    1. Omer SB, Enger KS, Moulton LH, Halsey NA, Stokley S, Salmon DA. Geographic clustering of nonmedical exemptions to school immunization requirements and associations with geographic clustering of pertussis. Am J Epidemiol. 2008;168(12):1389–96. - PubMed

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