The Correlation Between a New York State Law Repeal and Vaccine Coverage in Schools

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On June 13, 2019, the New York State (NYS) legislature passed Senate Bill 2994A, which repealed any nonmedical vaccination exemption options from school-entry immunization requirements, becoming the fifth US state to address the rise in pediatric undervaccination by repealing these options. This was as a result of two measles outbreaks occurring in the area.

A cohort study published in JAMA Network Open set out to investigate the repercussions of the NYS repeal at NYS schools outside of NYC. The study used Information and Reporting Services data from the 2012-2013 through 2021-2022 school years at schools that enrolled students from kindergarten to 12th grade (K-12). Race and ethnicity were also examined as demographic characteristics.

“While school-entry immunization requirements effectively promote and maintain high US pediatric vaccine coverage, less is known regarding the outcome of legislative repeals of nonmedical vaccination exemption options,” the study authors wrote. “Initial evaluations of a California repeal of school nonmedical vaccination exemptions suggest that although the legislation was effective to increase the percentage of kindergartners up-to-date for vaccinations, these increases were partially offset by simultaneous increases in student medical vaccine exemptions. In addition, new medical vaccination exemptions were found to spatially cluster, suggesting that the legislation did not have a uniform impact on vaccine compliance.”

The next step in the investigation was to combine the aforementioned Information and Reporting Services enrollment data with Department of Health School Immunization Survey data, whichmandates that participating schools provide the number of K-12 students with medical and nonmedical vaccination exemptions, along with students who met the grade-appropriate proof of immunity requirements for seven mandatory school-entry immunization.

The investigators explored the following outcomes:

1. Vaccine coverage, which is the annual percentage of students at each school who completed the grade-appropriate requirements for all required vaccines
2. Medical exemption uptake, also known as the percentage of students at each school who received a medical exemption

Out of the 3,821 schools that qualified, 3,632 were included in the actual study, which comes out to 95.1%. In total, these schools submitted 34,784 immunization reports, including a mean of 9.8 (95% CI, 9.8-9.8) reports among public schools and 8.9 (95% CI, 8.7-9.0) reports among the nonpublic schools.

The passing of Senate Bill 2994A resulted in absolute increases in mean vaccine coverage of 5.5% (95% confidence interval, or CI), 4.5%-6.6%) among nonpublic schools and 0.9% (95% CI, 0.7%-1.1%) among public schools; there was also a rise in vaccine coverage observed through the 2021-2022 school year.

In regard to the second outcome above, the law result in a 0.1% (95% CI, 0.0%-0.1%) mean absolute decrease in medical vaccination exemption uptake at both public and nonpublic schools, and annual decreases in medical vaccination exemptions (0.02%; 95% CI, 0.01%-0.03%) until the end of the study period. In essence, mean differences with CIs of 95% that did not cross 0% were deemed “statistically significant.”

“ … The repeal of nonmedical vaccination exemptions was associated with increases in mean vaccine coverage at NYS schools outside of NYC,” the study authors wrote. “Among these schools, evidence that coverage gains were offset by increasing medical exemptions was not found; instead, a small but significant decrease in medical exemptions associated with implementation of Senate Bill 2994A was observed. These findings suggest that a legislative repeal of school-entry nonmedical vaccination exemptions can be effective in increasing vaccination compliance without replacement by new medical exemptions.”

However, although the results could imply that this state legislation can be successful in boosting school vaccine coverage, it’s also important to note that the study period was only limited to three years following the passing of the legislation, which also happened to be the years of the COVID-19 pandemic.

Reference

Correira JW, Kamstra R, Zhu N, Doll MK. School Vaccine Coverage and Medical Exemption Uptake After the New York State Repeal of Nonmedical Vaccination Exemptions. JAMA Netw Open. 2024;7(2):e2354710. doi:10.1001/jamanetworkopen.2023.54710