Beliefs about causes of autism and vaccine hesitancy among parents of children with autism spectrum disorder.

Vaccine hesitancy may be more common among parents of children with autism spectrum disorder (ASD). We examined factors associated with ASD-specific vaccine hesitancy among caregivers of children with ASD who participated in the SPARK study (Simons Foundation Powering Autism Research for Knowledge). 225 participants completed an online survey containing the Parent Attitudes About Childhood Vaccines (PACV) questionnaire (measure of vaccine hesitancy) and the Illness Perception Questionnaire revised for parents of children with ASD (IPQ-R-ASD; measure of parents' views about ASD). 65 participants (28.8%) were vaccine hesitant (PACV score ≥ 50); children of vaccine-hesitant parents (VHPs) were less likely to be first born (n = 27, 41.5%), had greater ASD-symptom severity (mean Social Communication Questionnaire score = 23.9, SD = 6.9), and were more likely to have experienced developmental regression (n = 27, 50.9%) or plateau (n = 37, 69.8%). Compared to non-hesitant parents, VHPs significantly more often endorsed accident/injury, deterioration of the child's immune system, diet, environmental pollution, general stress, parents' negative views, parents' behaviors/decisions, parents' emotional state, and vaccines as causes for ASD. VHPs also had higher scores on the Personal Control, Treatment Control, Illness Coherence, and Emotional Representations subscales of the IPQ-R than did non-hesitant parents. In the final model, ASD-related vaccine hesitancy was significantly associated with higher scores on the Emotional Representations subscale (OR = 1.13, p = 0.10), agreement with deterioration of the child's immunity as a cause of ASD (OR = 12.47, p < 0.001), the child not having achieved fluent speech (OR = 2.67, p = 0.17), and the child experiencing a developmental plateau (OR = 3.89, p = 0.002). Findings suggest that a combination of child functioning and developmental history, as well as parents' negative views about and their sense of control over ASD, influence vaccine hesitancy among parents of children with ASD.