Contents lists available at ScienceDirect Social Science & Medicine journal homepage: www.elsevier.com/locate/socscimed Parent psychology and the decision to delay childhood vaccination Timothy Callaghan a,* , Matthew Motta b , Steven Sylvester c , Kristin Lunz Trujillo d , Christine Crudo Blackburn a a Texas A&M University, United States b Oklahoma State University, United States c Utah Valley University, United States d University of Minnesota, United States ARTICLE INFO Keywords: Vaccine delay Hesitancy Psychological correlates Health Psychology Parent Childhood vaccines ABSTRACT Objective: The study of vaccine hesitancy identifies parental decisions to delay childhood vaccinations as an important public health issue, with consequences for immunization rates, the pursuit of nonmedical exemptions in states, and disease outbreaks. While prior work has explored the demographic and social underpinnings of parental decisions to delay childhood vaccinations, little is known about how the psychological dispositions of parents are associated with this choice. We analyze public opinion data to assess the role of psychological factors in reported parental decisions to delay childhood vaccination. Rationale: We anticipate that parents with certain psychological characteristics will be more likely to delay childhood vaccination. Specifically, we explore the roles of conspiratorial thinking, dispositions towards needle sensitivity, and moral purity; expecting that parents with high levels of any of these characteristics will be more likely to delay vaccinating their children. Method: In an original survey of 4010 American parents weighted to population benchmarks, we asked parents about delay-related vaccination behavior, demographic questions, and several psychological batteries. We then developed a vaccination delay scale and modeled delay as a function of conspiratorial thinking, needle sensi- tivity, moral purity, and relevant demographic controls. We then re-specified our models to look specifically at the predictors of delaying HPV vaccination, which has a low uptake rate in the United States. Results: Controlling for other common predictors of hesitant behavior, we find that parents with high levels of conspiratorial thinking and needle sensitivity are more likely to report pursuing alternative vaccination sche- dules. When analyzing the specific decision by parents to delay HPV vaccination, we find that tendencies to- wards moral purity and, in turn, sexual deviance are also associated with vaccine seeking behavior. Conclusion: Parental decisions to delay childhood vaccinations are an important public health concern that are associated with conspiratorial thinking and needle sensitivity. 1. Introduction The development and widespread adoption of vaccines was one of the most important developments of the 20th century and is arguably the greatest accomplishment of the field of public health. Vaccines have been responsible for the eradication of diseases such as smallpox and prevent the emergence of diseases that used to be common like measles, mumps, and rubella. Nonetheless, anti-vaccine sentiment has grown considerably in the United States and across the globe over the past two decades (Joslyn and Sylvester, 2019; Larson et al., 2014; Motta et al., 2018). Fueled by now debunked research suggesting a link between vaccination and autism (Haberman, 2015), misinformation from celebrities and politicians (Benegal, 2018), and growing rates of autism diagnosis (CDC, 2018a), vaccine hesitancy has gained a foothold among many parents in the general public. Defined as the decision to delay vaccination or the refusal to vac- cinate despite available vaccination services, vaccine hesitancy has been identified as a growing problem of global importance by the WHO Strategic Advisory Group of Experts (SAGE) on Immunization (Dubé et al., 2014; Larson et al., 2015; Official, 2015; Salmon et al., 2015). Including individuals who “refuse some or all vaccines, delay some vaccines according to an alternative schedule, or accept all vaccines but remain concerned,” (Salmon et al., 2015, pp. 1–2) vaccine hesitancy represents a continuum of apprehension that has had important https://doi.org/10.1016/j.socscimed.2019.112407 Received 21 December 2018; Received in revised form 18 June 2019; Accepted 6 July 2019 * Corresponding author. 212 Adriance Lab. Rd., 1266 TAMU, College Station, TX 77843, United States. E-mail address: callaghan@tamu.edu (T. Callaghan). Social Science & Medicine xxx (xxxx) xxxx 0277-9536/ © 2019 Elsevier Ltd. All rights reserved. Please cite this article as: Timothy Callaghan, et al., Social Science & Medicine, https://doi.org/10.1016/j.socscimed.2019.112407