The landscape of childhood vaccine exemptions in the United States

"I Don't Understand How These Two Things Go Together": Toward a Theory of Risk Ecologies

Rhetorical ecological approaches, which posit that messages exist not as isolated entities but instead in the relations of a dynamic network, offer a valuable lens for examining the discursive construction of health-related risk. Drawing from interview data (n = 50) exploring maternal vaccine refusal, this article expands upon these frameworks to trace how intertextual, synchronous messages - particularly those associated with prenatal and infant nutrition - influence mothers' understanding about early childhood vaccine-related risk. Ultimately, I propose the notion of a risk ecology - a network of intertextual messages which shape and constrain sense-making about risk as it emerges within a particular moment and biosocial community.

Spatial distribution and determinants of childhood vaccination refusal in the United States

Parental refusal and delay of childhood vaccination has increased in recent years in the United States. This phenomenon challenges maintenance of herd immunity and increases the risk of outbreaks of vaccine-preventable diseases. We examine US county-level vaccine refusal for patients under five years of age collected during the period 2012-2015 from an administrative healthcare dataset. We model these data with a Bayesian zero-inflated negative binomial regression model to capture social and political processes that are associated with vaccine refusal, as well as factors that affect our measurement of vaccine refusal. Our work highlights fine-scale socio-demographic characteristics associated with vaccine refusal nationally, finds that spatial clustering in refusal can be explained by such factors, and has the potential to aid in the development of targeted public health strategies for optimizing vaccine uptake.

State of Vaccine Hesitancy in the United States

Although the term "vaccine hesitancy" has achieved great prominence, the extent to which US parents have reluctance, doubts, or indecision when it comes to vaccines recommended for children and how such hesitancy is manifest are unclear. A narrative review approach that placed emphasis on recent data and published work is used to surface evidence and insights into the current state of US parent vaccine hesitancy. The assessment finds evidence that ∼6% to 25% of parents may be vaccine hesitant, that hesitancy is higher for influenza and HPV vaccines, and there are indications that addressing parent hesitancy has become more challenging.

Spatial clustering in vaccination hesitancy: The role of social influence and social selection

The phenomenon of vaccine hesitancy behavior has gained ground over the last three decades, jeopardizing the maintenance of herd immunity. This behavior tends to cluster spatially, creating pockets of unprotected sub-populations that can be hotspots for outbreak emergence. What remains less understood are the social mechanisms that can give rise to spatial clustering in vaccination behavior, particularly at the landscape scale. We focus on the presence of spatial clustering, and aim to mechanistically understand how different social processes can give rise to this phenomenon. In particular, we propose two hypotheses to explain the presence of spatial clustering: (i) social selection, in which vaccine-hesitant individuals share socio-demographic traits, and clustering of these traits generates spatial clustering in vaccine hesitancy; and (ii) social influence, in which hesitant behavior is contagious and spreads through neighboring societies, leading to hesitant clusters. Adopting a theoretical spatial network approach, we explore the role of these two processes in generating patterns of spatial clustering in vaccination behaviors under a range of spatial structures. We find that both processes are independently capable of generating spatial clustering, and the more spatially structured the social dynamics in a society are, the higher spatial clustering in vaccine-hesitant behavior it realizes. Together, we demonstrate that these processes result in unique spatial configurations of hesitant clusters, and we validate our models of both processes with fine-grain empirical data on vaccine hesitancy, social determinants, and social connectivity in the US. Finally, we propose, and evaluate the effectiveness of two novel intervention strategies to diminish hesitant behavior. Our generative modeling approach informed by unique empirical data provides insights on the role of complex social processes in driving spatial heterogeneity in vaccine hesitancy.

Preventable Disease, the Case of Colorado: School District Demographics and Childhood Immunizations

The objective of this study was to evaluate the impact of selected sociodemographic factors on childhood vaccination hesitancy and to define their role according to specific exemptions. This population-based cohort study utilized vaccination rate and sociodemographic data from 1st to 12th grade from 2017 to 2021 for all school districts in Colorado. Data included immunization status and exemptions for each vaccine, race, ethnicity, and free and reduced meal status. Data were evaluated through dimensional analysis and Generalized Linear Mixed Models. School districts with a higher representation of White students had lower immunization rates and use more personal exemptions while school districts with larger Hispanic populations and higher proportions of free and reduced lunches had higher vaccination rates and used more religious exemptions. Black and Pacific Islander populations had higher rates of incomplete vaccination records while Asian American population displayed increased vaccination compliance. Colorado is a robust example of how socioeconomic and cultural differences are important factors with a direct influence on vaccination rates. Future childhood vaccination campaigns and legislation should consider complex socioeconomic and cultural factors.

Revisiting the 2014-15 Disneyland measles outbreak and its influence on pediatric vaccinations

The 2014-15 Disneyland measles outbreak that began at the California theme park in December 2014 sparked an international conversation regarding measles, vaccine hesitancy, and vaccine policies. The outbreak capped a year with the highest number of measles cases reported in two decades and came amidst increasing trends in nonmedical vaccine exemptions in California and elsewhere. Because of its sensational story line and spread among unvaccinated populations, the outbreak received a high level of media coverage that focused on vaccine hesitancy as a primary driver of the outbreak. This media coverage and the ostensible public support for vaccines that followed led some to hypothesize that the outbreak might have a "Disneyland effect," or a positive influence on the uptake of pediatric measles vaccine. This article reviews the facts of the outbreak and its context, and explores the evidence for the Disneyland outbreak causing an influence on U.S. pediatric vaccine-related beliefs and behaviors.