Impact of governmental regulations on compliance with MMR immunizations in Northern California

Objective: California's Senate Bill 277 (SB277) was mandated to reduce the prevalence of measles by eliminating personal belief exemptions. This study evaluated seven county-level records to determine the impact of SB277 on immunizations among kindergarteners in Northern California. Design: This study used a quantitative postintervention secondary data analysis. Sample: This study included three kindergarten schools in seven Northern California counties during three academic years from 2015 to 2019. Measurements: Sixty-three previously collected school measurements involving 4,626 students were included in a secondary analysis. The study used grouped logistic regression to evaluate the variations in immunization compliance records (2015–16 vs. 2017–18 and 2018–19) among kindergartners in seven counties. Results: This study found no significant differences in (1) overall county-level measures and (2) the likelihood that kindergartners would be current with measles–mumps–rubella (MMR; OR = 1.12, CI = 0.79–1.62) or be up-to-date with five immunizations (OR = 1.08, CI = 0.77–1.52) post-SB277 versus pre-SB277. Conclusion: This study showed that SB277 had a small clinical but nonstatistically significant impact on kindergartners' up-to-date with up-to-date rates of compliance with five immunizations and those current with two doses of MMR in seven Northern California counties. Despite the passing of SB277, vaccine-hesitant parents have continued to seek alternatives to immunizations.