The passage of SB 277 was anything but a foregone conclusion. Although California’s predominantly liberal populace generally tolerates assertive public health policies, a vocal libertarian minority ardently opposes vaccination mandates. The bill’s opponents mobilized fiercely against it, attending hearings with toddlers in tow and organizing strident protests. The pediatrician-senator who sponsored the bill received death threats.
Nevertheless, four factors converged to enable its passage. First, legislative supporters showed extraordinary backbone in resisting pressure to abandon the measure. Second, the DPH publicized data showing that rates of personal-belief exemptions in California have doubled since 2007,1 and analysts noted that vaccination coverage is low enough to jeopardize herd immunity in a quarter of schools.2 Third, the widely publicized Disneyland measles outbreak brought home the risks posed by lost herd immunity. Researchers swiftly concluded that “substandard vaccination compliance is likely to blame for the 2015 measles outbreak.”3 The outbreak created a political opening and energized legislators, parents, and interest groups that aren’t ordinarily activated around vaccination issues.