California Senate Bill 277’s Grandfather Clause and Nonmedical Vaccine Exemptions in California, 2015-2022 | Law and Medicine | JAMA Pediatrics | JAMA Network
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Research Letter
June 2016

California Senate Bill 277’s Grandfather Clause and Nonmedical Vaccine Exemptions in California, 2015-2022

Author Affiliations
  • 1Department of Geography, George Mason University, Fairfax, Virginia
  • 2Department of Health Administration and Policy, George Mason University, Fairfax, Virginia
JAMA Pediatr. 2016;170(6):619-620. doi:10.1001/jamapediatrics.2015.4856

On June 25, 2015, California’s governor approved Senate Bill (SB) 277, a state law that substantially narrows exceptions to school-entry vaccination mandates. The law goes into effect on July 1, 2016, and California will join Mississippi and West Virginia as the third state to disallow nonmedical exemptions (NMEs) from vaccination based on religious or philosophical beliefs for students entering public or private schools.1 Only medical exemptions will be permitted.

In a compromise during the legislative process in May 2015, the SB 277 authors included a “grandfather clause” that allows students who already possess an NME to continue attending school without vaccination until their next vaccination grade checkpoint (seventh grade in California).2 Although the decision to grandfather students with a pre–SB 277 NME reduces the potential for conflict between schools and vaccine-hesitant parents, it also allows students with NMEs to remain within California’s schools in the near future. We provide, to our knowledge, the first detailed estimates of the effects of SB 277’s grandfather clause on NMEs in California’s schools.


Using Immunization Assessment Results from the California Department of Public Health and projected enrollment from the Department of Education, we estimated the number of students with an NME in California schools (kindergarten through 12th grade) from 2015 to 2022. To calculate enrollment and NMEs for the entire school system, we combined kindergarten data from 2008 to 2015, seventh- through 12th-grade data from 2011, seventh-grade data from 2012 to 2014, and projected school enrollment data for 2016 to 2022 to construct a set of cohort groups that advance through the system (eg, kindergarteners in 2008 would be sixth graders in 2015). The most recent observed enrollment data were used where applicable. We estimated kindergarten enrollment from 2016 to 2022 using the projected yearly change. In our model, students having a pre–SB 277 NME remained unvaccinated until they reached seventh grade or left the system via graduation. Starting in 2016, owing to SB 277, we assigned a 0% NME rate for all students entering kindergarten and seventh grade, the state’s 2 vaccine checkpoints.3

Institutional review board approval was not required for this research because all data used in the analysis were nonidentifiable and publicly available online from the State of California’s Department of Community Health and Department of Education.


The 2015 to 2022 yearly NME estimates show how SB 277’s grandfather clause will affect NMEs in California over time (Table). We estimated that the number of students with an NME rose to 164 148 (2.45% of all students) in 2015 and will begin to steadily decline after SB 277 is implemented in 2016. We estimated that the number of students with NMEs in the school system will not fall below 100 000 until 2018 and not below 50 000 until 2020. Although no kindergarten or seventh-grade student will be allowed to enter the school system with an NME after 2015, the combination of SB 277’s grandfather clause and the 2-checkpoint system will allow a substantial number of students with an NME to attend California schools until 2021.

Table.  Estimated Nonmedical Exemptions in California Schools (K–12th Grade), 2015-2022
Estimated Nonmedical Exemptions in California Schools (K–12th Grade), 2015-2022


Senate Bill 277’s grandfather clause was included as a compromise that increased the chance of the law’s passage by mollifying California parents concerned with vaccine adverse effects and their parental rights. Although SB 277 is a strong legislative measure that will improve vaccination coverage in California’s schools by removing NMEs, we estimate that the full benefits of the law will not be realized until the 2022 school year.

In California, vaccine uptake and NME rates for school-age children vary considerably from neighborhood to neighborhood, forming pockets wherein a large proportion of children are unvaccinated.4,5 The grandfather clause in SB 277 will allow many of these pockets to persist into the near future. Areas with low vaccination uptake have been shown to have a higher risk of vaccine-preventable disease outbreaks.6 Therefore, some California neighborhoods will continue to be at risk for measles or pertussis outbreaks until NMEs are fully eliminated from the school system in 2022.

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Article Information

Corresponding Author: Paul L. Delamater, PhD, Department of Geography, George Mason University, 4400 University Dr, MSC63, Fairfax, VA 22030 (

Correction: There was an error in the Table. The number (%) of nonmedical exemptions for the 2015 kindergarten population should be 13 086 (2.37). This number and percentage should also replace the original numbers and percentages for the 2016 first-grade population, the 2017 second-grade population, the 2018 third-grade population, the 2019 fourth-grade population, the 2020 fifth-grade population, and the 2021 sixth-grade population. The total number (%) of medical exemptions for each year should be 164 148 (2.45) for 2015, 143 114 (2.12) for 2016, 120 362(1.77) for 2017, 94 073 (1.38) for 2018, 63 269 (0.92) for 2019, 36 207 (0.52) for 2020, and 13 086 (0.19) for 2021. This article was corrected online on April 25, 2016.

Published Online: March 28, 2016. doi:10.1001/jamapediatrics.2015.4856.

Author Contributions: Dr Delamater had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: All authors.

Acquisition, analysis, or interpretation of data: Delamater.

Drafting of the manuscript: All authors.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Delamater.

Administrative, technical, or material support: Delamater.

Study supervision: Yang.

Conflict of Interest Disclosures: None reported.

S 277, 2015-2016 Leg, Reg Sess (Ca 2015).
California Legislative Information. Bill history: SB-277 public health: vaccinations. Accessed September 12, 2015.
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