170. Association between Social Determinants of Health and Completion of the HPV Vaccine Series

The 2-dose 9-valent human papillomavirus (HPV) vaccine is nearly 100% effective in preventing precancerous lesions if completed before sexual initiation. However, only 16% and 35% of adolescents have completed the series before their 13th and 15th birthdays, respectively. Most studies assessing factors associated with HPV vaccine completion have focused on the 3-dose series, and results regarding the role of social determinants of health (SDOH) in series completion are inconsistent, especially SDOH such as food security, housing, and healthcare, as well as physical safety and mental health. Therefore, the purpose of this study was to determine the association between SDOH and completion of the 2-dose HPV vaccine series. We conducted a retrospective electronic medical record review of patients 11-15 years of age (N=300) who were attending two pediatric primary care clinics at an urban academic medical center and who had initiated the 2-dose HPV vaccine series between October 2020 and March 2021. Participant demographics, influenza vaccination status, HPV vaccination initiation and completion dates, missed opportunities for HPV vaccination, clinic visit type, and SDOH variables were abstracted. SDOH variables included food insecurity, parent/caregiver depression, challenges accessing resources (e.g., Women, Infants Children Program, Supplemental Nutrition Assistance Program), housing problems, eviction or loss of one’s home, challenges paying for medications, challenges accessing transportation to medical appointments or pharmacy, and history of trauma. Independent variables associated with completing the HPV vaccine series at p < .10 in univariable analysis were eligible for inclusion in the multivariable logistic regression models. Among patients who initiated the HPV vaccine series in the study period, 182/300 (61%) completed the vaccine series: 148 (49.3%) females and 152 (50.7%) males. The mean age of HPV vaccine initiation was 11.6 years of age. Seventy-seven percent of patients were African American, 4% were Hispanic, 86.3% had Medicaid or Caresource, and 54% had declined the influenza vaccine. In a multivariable model, having received an influenza vaccine was the only variable significantly associated with HPV vaccine series completion (adjusted odds ratio 2.01; 95% confidence interval 1.11 - 3.65). In this study, SDOH were not associated with HPV vaccine completion. However, vaccination preferences may be shaped by SDOH, as supported by the association between influenza vaccination and HPV vaccine series completion such as access to information and accessing medical care (e.g., access to transportation for medical appointments) may impact vaccine uptake. Additional studies are needed to better understand the role of SDOH in vaccine series completion. In the meantime, given that a strong and consistent provider recommendation for HPV vaccination has been shown to be one of the strongest predictors of vaccination, interventions to improve provider communication and recommendation skills should be enhanced to address HPV vaccine series completion.