Getting Personal: How Childhood Vaccination Policies Shape the Landscape of Vaccine Exemptions

Abstract

Background State-mandated school entry immunization requirements in the United States play an important role in achieving high vaccine coverage, but variations in vaccine exemption policies result in a patchwork of vaccine coverage across the country. Methods In this study, we evaluate epidemiological effects and spatial variations in nonmedical exemption (NME) rates in the context of vaccine policies. We first analyze the correlation between NME rates and vaccine coverage for 3 significant childhood vaccinations. Furthermore, we assess the effects of policy changes in a subset of states, using a correlative approach at the state level and performing a clustering analysis at the county level. Results We find that higher rates of exemptions are associated with lower vaccination rates of school-aged children in all cases. In a subset of states where exemption policy has recently changed, we show that the effects on statewide NME rates vary widely and that decreases in NMEs can lead to an increase in other types of exemptions. Finally, our clustering analysis in California, Illinois, and Connecticut shows that policy changes affect the spatial distribution of NMEs. Conclusions Our work suggests that vaccination policies have significant impacts on patterns of herd immunity. Our findings can be used to develop evidence-based vaccine legislation.

The landscape of childhood vaccine exemptions in the United States

“…The case of California highlights the importance of studying exemption trends across time. We see that there is a plunge in exemptions following the removal of non-medical exemptions followed by an increase in the exemption level, perhaps indicating that vaccine hesitant individuals found other means to obtain exemptions 3,4,18 . Figure 4 demonstrates total exemptions across data reported years by state, broken down into medical exemptions, religious exemptions, philosophical exemptions, or unknown.…”

“…In the United States, the resurgence of once-eliminated diseases such as measles has reignited discussions over the role of vaccine hesitancy in diminishing herd immunity 2 . State-mandated school entry immunization requirements in the United States play an important role in achieving high vaccine coverage, but variations in vaccine exemption policies result in a patchwork of vaccine coverage across the country 3 . In all states, medical exemptions from immunizations can be obtained for conditions such as those resulting in immunosuppression or in cases of known adverse reaction to past immunizations.…”

“…However, this spatial scale is largely inadequate as both exemptions and vaccine preventable childhood disease cases tend to cluster at smaller spatial scales 11 . Many prior studies have been performed at smaller scales, from the county to the school levels 3,[12][13][14][15] . However, the datasets used in these studies tend to be limited both in time and in terms of the spatial area they cover.…”

In the Wake of a Pandemic: Revisiting School Approaches to Nonmedical Exemptions to Mandatory Vaccination in the US

“…[ 10 , 15 , 16 ] For measles and pertussis increased rates of exemption have led to increased incidence of these diseases, with significant consequence. [ 17 , 18 ]…”

The landscape of childhood vaccine exemptions in the United States

“…In the United States, the resurgence of once-eliminated diseases such as measles has reignited discussions over the role of vaccine hesitancy in diminishing herd immunity [2]. State-mandated school entry immunization requirements in the United States play an important role in achieving high vaccine coverage, but variations in vaccine exemption policies result in a patchwork of vaccine coverage across the country [3]. In all states, medical exemptions from immunizations can be obtained for conditions such as those resulting in immuno-suppresion or in cases of known adverse reaction to past immunizations.…”