Abstract
Objectives. To evaluate trends in rates of personal belief exemptions (PBEs) to immunization requirements for private kindergartens in California that practice alternative educational methods.
Methods. We used California Department of Public Health data on kindergarten PBE rates from 2000 to 2014 to compare annual average increases in PBE rates between schools.
Results. Alternative schools had an average PBE rate of 8.7%, compared with 2.1% among public schools. Waldorf schools had the highest average PBE rate of 45.1%, which was 19 times higher than in public schools (incidence rate ratio = 19.1; 95% confidence interval = 16.4, 22.2). Montessori and holistic schools had the highest average annual increases in PBE rates, slightly higher than Waldorf schools (Montessori: 8.8%; holistic: 7.1%; Waldorf: 3.6%).
Conclusions. Waldorf schools had exceptionally high average PBE rates, and Montessori and holistic schools had higher annual increases in PBE rates. Children in these schools may be at higher risk for spreading vaccine-preventable diseases if trends are not reversed.
Increasing rates of exemptions to immunization requirements among kindergarteners in the United States have raised concerns about outbreaks of vaccine-preventable diseases in the 21st century.1–7 Parents in many states can obtain nonmedical exemptions to kindergarten immunization requirements because of personal beliefs and religion.8,9 In California, the rate of personal belief exemptions (PBEs) doubled from 1.2% to 2.3% from 2004 to 2010.4 Children with exemptions are clustered geographically and socially, potentially leading to novel outbreaks of vaccine-preventable diseases, making it critical to examine possible heterogeneity of immunization coverage within states.1,3,6,10
Previous research has shown that PBE rates differ between children enrolled in public and private schools.11–16 For example, the average PBE rate among private schools was nearly double the rate for public schools in California in the past decade.13 There is limited research on community factors that may influence increasing PBE rates in specific areas or groups, which could be used to try to intervene on increasing exemption trends. It is known that nonmedical exemptions are associated with high socioeconomic status and lower average family size, and that high PBE rates are associated with charter and private schools, schools with high proportions of White students, schools in areas of higher income, schools with low prevalence of free or reduced-price lunches, schools with higher tuition fees, and schools that follow secular doctrines.6,9,11,12,16
Specific education methods used in schools may be representative of underlying community factors that could be associated with increased exemption rates. Community factors that previously have been associated with high PBE rates may correlate with attendance of a child in a particular school.6,9,11,12,16 Vaccine-preventable diseases could easily be spread through groups of children with low vaccine coverage, and so it is critical to grasp the extent of vaccine exemption in specific school populations to prevent such outbreaks. If certain education methods are found to be associated with high exemption rates, then knowledge of beliefs and traits shared by parents in these specific education settings may also provide key information that could be used to target public health interventions to these parents and communities. Exemption trends for specific types of private schools, such as alternative schools, including Waldorf and Montessori schools, have not been investigated previously in the United States. We evaluated trends in PBE rates for private schools in California that follow specific alternative educational methods, and compared those rates to the PBE rates for public schools over the course of a 14-year period.
METHODS
We acquired data on PBE rates for all California public and private schools from the California Department of Public Health (CDPH) for the 2000–2001 through 2014–2015 school years. Data for the earlier years had to be requested from the CDPH, and data for more recent years were publicly available. In the data set, school-level PBEs were presented as both counts and rates for each school year. The PBE rates were reported in the original data set as the number of enrolled students with PBEs in that school divided by the total enrollment for that school, specific to each school year. We combined the data sets for each school year into a single data set for final analysis.
We next classified schools by specific type of private alternative school (Figure 1). To further examine the exemption trend noticed between public and private schools, alternative schools had to be private schools. It is possible that not all of the alternative schools would be captured by searching through only the private schools, but this method provided a verifiable list of private alternative schools. The data set already included a dichotomous variable that categorized the schools as being public or private, which allowed us to search through the private schools to identify and categorize the alternative schools.
FIGURE 1—
Flowchart of Methods Used to Classify Schools in Data Set by School Type
From a list of private schools contained in the data set, we searched for each private school’s provided street address in an Internet search, and checked the search results with the school name provided in the original data set. We categorized each private school by using 2 variables, based on information provided by each school’s philosophy and mission value statements on Web site pages. We used a dichotomous variable to designate the school as following an alternative education method (1 = alternative; 0 = not alternative), and a categorical variable to designate the specific type of alternative method that the school followed.
Religious and traditional private schools were not categorized as private alternative schools in the final analysis. Schools that were categorized as private alternative schools in the final analysis included Waldorf, Montessori, holistic, progressive, day, international, and experiential schools. To be categorized as a Montessori or Waldorf school, the school had to claim to follow the Montessori or Waldorf methods or be inspired by these methods on their Web page. The schools that were designated to be holistic schools did not describe an exact education method in their Web pages, but did use the phrases “whole child” or “holistic” specifically in philosophy and mission value statements.17 The school categories examined in the analysis were Montessori schools, Waldorf schools, and holistic schools (all considered separately); those 3 alternative school types combined (“overall”); all private alternative school types combined; and all public schools.
We computed the average PBE rates across the entire 14-year study period for each school category. We used generalized estimating equations based on the negative binomial distribution to estimate incidence rate ratios (IRRs) for change in the average PBE rate over the study period, with a cluster term for each school to account for correlated observations. We removed public and private schools from analyses for a particular year if the school was missing PBE rate data for that year (n = 1367); schools with data missing only for some years were retained for the years in which exemption rate data were present. The specific schools in each school category could vary by year. Therefore, the exact same schools did not have to be represented in every year of data across the 14-year period to be included in the analysis.
We first modeled the average annual increase in PBE rates across all alternative schools and across all public schools. Second, we stratified the analyses by alternative school type, using Montessori schools, Waldorf schools, holistic schools, and a category of these 3 school types combined (“overall”). We interpreted estimated IRRs as average annual increases in PBE rates from IRRs; for example, an IRR of 1.073 (95% confidence interval [CI] = 1.070, 1.076) would translate into an average annual increase in the PBE rate of 7.3% (95% CI = 7.0%, 7.6%). Third, we estimated IRRs comparing the average PBE rates between all school category types and the public schools. We did not adjust analyses for potential confounders because of the limited covariate data available. Demographic data were not available in this data set, other than county and city location of each school. We performed all statistical analyses by using SAS version 9.4 (SAS Institute Inc, Cary, NC).
RESULTS
Alternative and public schools contributed 84 227 school-years of data across the 14-year period (Table 1). A total of 6656 public schools contributed 81 002 school-years of data. In addition, 147 Montessori schools, 20 Waldorf schools, and 35 holistic schools contributed a total of 2413 school-years of data. The school types with the highest PBE rates contributed consistent levels of school-years for each year. The Montessori schools were the most represented type of school among the alternative schools.
TABLE 1—
Sample Sizes by Year for Different School Types Considered in the Final Analysis of Personal Belief Exemption Rates: California, School Years 2000–2001 to 2014–2015
School Type, No. |
||||||
School Years | Public | All Alternative | Overall Alternativea | Montessori | Waldorf | Holistic |
2000–2001 | 5 092 | 231 | 173 | 124 | 18 | 31 |
2001–2002 | 5 172 | 235 | 180 | 126 | 20 | 34 |
2002–2003 | 5 203 | 233 | 178 | 128 | 19 | 31 |
2003–2004 | 5 251 | 225 | 170 | 118 | 19 | 33 |
2004–2005 | 5 286 | 227 | 170 | 121 | 18 | 31 |
2005–2006 | 5 364 | 228 | 173 | 122 | 20 | 31 |
2006–2007 | 5 423 | 229 | 171 | 123 | 18 | 30 |
2007–2008 | 5 440 | 222 | 164 | 113 | 19 | 32 |
2008–2009 | 5 443 | 226 | 173 | 123 | 19 | 31 |
2009–2010 | 5 443 | 227 | 171 | 121 | 19 | 31 |
2010–2011 | 5 507 | 209 | 155 | 103 | 20 | 32 |
2011–2012 | 5 572 | 205 | 153 | 108 | 20 | 25 |
2012–2013 | 5 578 | 204 | 151 | 102 | 20 | 29 |
2013–2014 | 5 584 | 168 | 118 | 73 | 18 | 27 |
2014–2015 | 5 644 | 156 | 113 | 74 | 15 | 24 |
Total | 81 002 | 3 225 | 2 413 | 1 679 | 282 | 452 |
Overall alternative = Waldorf, Montessori, and holistic schools combined.
The Waldorf schools had the highest average PBE rate of 45.1% across the study period (Table 2). The holistic schools had the second-highest PBE rate of 7.4%. Among the alternative schools analyzed, the Montessori schools had the lowest average PBE rate at 3.9% across the study period. Public schools had the lowest average PBE rate of 2.1% across the study period.
TABLE 2—
Personal Belief Exemption Rates, Stratified by School Type: California, School Years 2000–2001 to 2014–2015
School Type | School-Years, No. | Average PBE Rate, % | Annual % Change in Average PBE Rate (95% CI) | IRR (95% CI) |
Public | 81 002 | 2.1 | 7.3 (7.0, 7.6) | 1 (Ref) |
All alternative | 3 225 | 8.7 | 7.5 (4.2, 10.9) | 3.6 (2.9, 4.4) |
Overall alternativea | 2 413 | 9.4 | 5.5 (4.2, 6.8) | 3.9 (3.1, 4.8) |
Waldorf | 282 | 45.1 | 3.6 (2.6, 4.6) | 19.1 (16.4, 22.2) |
Holistic | 452 | 7.4 | 7.1 (4.5, 9.7) | 3.0 (2.2, 4.2) |
Montessori | 1 679 | 3.9 | 8.8 (6.3, 11.4) | 1.6 (1.3, 2.0) |
Note. CI = confidence interval; IRR = incidence rate ratio; PBE = personal belief exemption.
Overall alternative = Waldorf, Montessori, and holistic schools combined.
The average PBE rate for public schools increased from 0.9% during the 2000–2001 school year to 2.8% during the 2014–2015 school year, an average annual increase of 7.3% (95% CI = 7.0%, 7.6%; Table 2; Figure 2). By comparison, the average PBE rate increased from 5.1% to 10.8% for all alternative schools in the 14-year period, an average annual increase of 7.5% (95% CI = 4.3%, 6.7%; Table 2; Figure 2). Among the alternative schools, the average PBE rate for Montessori schools increased from 2.2% to 4.4% across the study period, an average annual increase of 8.8% (95% CI = 6.3%, 11.4%). The average PBE rate for holistic schools increased from 3.9% to 11.2% in the 14-year period, an average annual increase of 7.1% (95% CI = 4.5%, 9.7%). The average PBE rate for Waldorf schools increased from 30.3% to 48.2% across the study period, an average annual increase of 3.6% (95% CI = 2.6%, 4.6%). The average annual increases in PBE rates were similar for the Montessori, holistic, and public schools (Table 2).
FIGURE 2—
Average Personal Belief Exemption Rates by School Type: California, 2000–2014
The PBE rate among Waldorf schools was 19 times higher than the rate for public schools (IRR = 19.1; 95% CI = 16.4, 22.2; Table 2). The next highest PBE rate, compared with public schools, was among the holistic schools (IRR = 3.0; 95% CI = 2.2, 4.2). The PBE rate among Montessori schools was slightly higher than the rate for public schools (IRR = 1.6; 95% CI = 1.3, 2.0). Overall, these types of alternative schools combined had a PBE rate that was almost 4 times higher than public schools (IRR = 3.9; 95% CI = 3.1, 4.9). When all alternative schools were compared with public schools, the PBE rates were 3.6 times higher than the rates for public schools (95% CI = 2.9, 4.4).
The Waldorf schools had the highest rate of PBEs compared with the public schools (IRR = 19.1; 95% CI = 16.3, 22.1), but the Waldorf schools had the lowest annual change in average PBE rate (3.6%; 95% CI = 2.6%, 4.6%; Table 2). The Waldorf schools had by far the highest baseline PBE rate across all school types included in the final analysis, with an average PBE rate of 45.1%. The next highest average PBE rate was 7.4% for the holistic schools. The Montessori schools had a similarly lower average PBE rate of 3.9%.
DISCUSSION
We examined the trends in PBE rates among private alternative schools by using a comprehensive data set including California kindergartens from 2000 through 2014. These findings provide evidence of heterogeneous trends in PBE among private alternative schools, beyond the delineation between public and private schools previously described.11–16 Overall, the PBE rates increased across all alternative school types considered in the analysis at a higher rate than in public schools. Concerns should be raised about both the high overall average rate of PBEs among Waldorf schools, and the high rate of annual change in the Montessori and holistic alternative schools. The overall rate of PBEs for Waldorf schools over the study period was alarmingly high (45.1%), and that rate was still climbing, even if at a lower rate than the other alternative schools. The average annual PBE rates for Montessori and holistic schools were lower, with rates of 7.4% and 3.9%, respectively. However, it is still critical to target these schools because the annual increases in rates among the Montessori and holistic schools were the highest among the alternative schools.
There was no difference in the school-year contributions for schools with high or low PBE rates, indicating that there was not a systematic attempt to downplay reports of high PBE rates among certain school types. Smaller sample sizes for some of the alternative school categories could have affected the wider CIs present in the results, particularly for Waldorf schools. It is also important to note that, even with these high exemption rates, the alternative schools that we analyzed were a smaller subset of the overall student population in California.
There may be important distinguishing characteristics of the populations attending different private alternative schools. Parents seeking vaccine exemptions for their children are more likely to seek alternative nonhospital childbirth settings, to seek chiropractic health care for their children, and to distrust medical doctors, and they are less likely to use print materials compared with vaccinating parents.18 Alternative schools exist on a spectrum of beliefs and methods, and antivaccine beliefs may be embraced and reinforced in Waldorf schools more than in other alternative schools on the basis of an ideology focused on natural experiences and life choices. One study found that parents of children at a well-established US Waldorf school were highly educated and involved in health decisions for their children, and overwhelmingly viewed vaccination of children to be unnecessary, toxic, developmentally inappropriate, and profit-driven.19 Vaccine refusal among these parents after enrollment increased in the school, implying a socially cultivated reinforcement of vaccine refusal in Waldorf schools.19
Our findings provide evidence that can be used in addressing the increasing rates of PBEs in states that still allow PBEs, with legislation and intervention programs targeting parents of children within these private alternative schools, specifically Waldorf schools. Interventions that focus on working with populations that hold ideologies focused on natural experiences and alternative life choices will be most effective in reversing this trend of increasing exemptions. However, parents with stalwart antivaccine beliefs, rather than hesitancy toward vaccinations, prove to be extremely challenging.
A major strength of the study was the robust method used to categorize private schools by educational method (i.e., online search by school street address and review of school Web sites). These methods captured all of the alternative schools in the available data set, rather than only using the data for alternative schools present on unofficial online lists. It is possible that a certain level of misclassification could have been introduced through the potentially subjective nature of how we categorized the holistic schools.
Our study did not include census tract–level data in the analysis, because previous articles have noted the potential issue that census tract data may not accurately reflect the data for students that attend private schools.3 We were unable to investigate the relationship between location of residence and school location at this time because we did not have individual data on location of residence for the private schools. Our objective was to describe trends across alternative school types compared with public schools; therefore, we did not adjust our analyses for census tract–level data. In addition, our data set limited our investigation of the differing magnitudes of average rates and annual changes in rates among these types of alternative schools, and further research into possible factors driving this phenomenon would greatly expand our understanding of these trends. As previously discussed, other factors and confounders present in these school communities may influence exemption rates, and an adjusted analysis that controls for these influencing factors would be beneficial to improving understanding of this phenomenon of increasing exemption rates in specific populations of children.
Personal belief exemptions to school immunization requirements became restricted in California after the passage of Senate Bill 277 in June 2015.8 After the law came into effect in July 2016, only homeschooled children in California were allowed nonmedical exemptions to immunization requirements. Children without a medical exemption are now required to have up-to-date vaccines. The new law applies to both public and private elementary schools, secondary schools, and daycare centers. As a result, trends in PBE rates in California will change, and possible trends should be investigated in the future. It will be important to investigate the implementation of this new law, as well as the potential for variability in local enforcement and ease of obtaining the new exemption for homeschooled children.20
The results of this analysis will also be useful elsewhere in the United States, where alternative education methods are also popular. Waldorf, Montessori, holistic, and other alternative education methods are not unique to the state of California. Our findings demonstrating increasing rates of PBEs and heterogeneity among private alternative schools in California may likely reflect national trends. Control of vaccine-preventable diseases requires “indefinite maintenance of extremely high rates of timely vaccination.”20(pS391) Public health practitioners and concerned parties should remain vigilant and work to understand underlying specific community factors when attempting to develop and maximize the efficacy of interventions aimed at addressing vaccine refusal and vaccine hesitancy.
ACKNOWLEDGMENTS
The authors would like to thank the California Department of Public Health for the use of the publicly unavailable data for the analysis.
Ms. Richards received support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health (NIH) T32 Predoctoral Training Program in Reproductive, Perinatal, and Pediatric Epidemiology (award number T32HD052460).
HUMAN PARTICIPANT PROTECTION
Approval of the use of the data was received from the California Committee for the Protection of Human Subjects, the Emory University institutional review board, and the California institutional review board.
Footnotes
See also Kim-Farley, p. 15.
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