Abstract A162: Structural and familial predictors of HPV vaccination among Latino adolescents: Exploring drivers of cancer prevention disparities

Abstract Objective: This study investigates how maternal healthcare access barriers and sibling birth order influence HPV vaccine initiation and completion among Latino adolescents in Los Angeles. Background: Cervical cancer disproportionately impacts Latina women in the United States. While human papillomavirus (HPV) vaccination is a highly effective prevention method, uptake among Latino adolescents remains suboptimal. Prior research has identified cultural and informational barriers in Latino communities, but fewer studies have examined how structural barriers to healthcare, such as lacking health insurance or a regular primary care provider, may influence vaccination behaviors. Additionally, limited attention has been given to how family dynamics, such as sibling birth order, may affect vaccine initiation and completion. Methods: This cross-sectional study used maternal survey data collected as part of the Es Tiempo campaign (2016–2018) in Los Angeles. The analytic sample included 353 children aged 9–26 reported by 238 Latina mothers. Descriptive statistics and chi-square tests were used to assess bivariate relationships between vaccination status, child sex, and birth order. Logistic regression models were used to examine the association between maternal healthcare barriers and HPV vaccine initiation and completion. Multilevel mixed-effects logistic regression and cumulative link mixed models were used to evaluate the relationship between birth order and vaccine uptake, accounting for clustering of siblings within families. Results: Forty-four percent of children initiated the HPV vaccine series, and 23% completed it. Initiation was higher among girls than boys. Children whose mothers lacked health insurance or access to a regular provider had lower odds of initiating the vaccine, and firstborn children had higher odds of initiating vaccination compared to later-born siblings. In contrast, later-born children had modestly higher odds of completing the series. Ordinal models showed a 16% decline in the odds of receiving more doses with each increase in birth order. Older child age was also associated with lower odds of cumulative dose uptake. Conclusion: Both maternal healthcare barriers and sibling birth order appear to influence HPV vaccination behaviors. These findings suggest that structural barriers and within-family dynamics should be considered when designing interventions to improve HPV vaccine uptake in Latino communities. Further research is needed to explore how family size, age, and access to care jointly shape vaccine adherence patterns. Citation Format: Anju F. Kane, Lourdes Baezconde Garbanati. Structural and familial predictors of HPV vaccination among Latino adolescents: Exploring drivers of cancer prevention disparities [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A162.