Correlates of HPV Vaccine Initiation, Completion, and Dosing Intervals among Female and Male Adolescents in Inner-City Community Health Centers for 2011-2013

Purpose: The human papillomavirus (HPV) infection is a known risk factor for the development of several cancers. According the CDC, between 2004 and 2008, there was a national average of 33,369 HPV-associated cancers annually, including cervical, vulvar, vaginal, penile, anal, and oropharyngeal cancers. There are pervasive disparities in national morbidity and mortality rates in the US for HPV-related cancers among Black and Hispanic. Cervical cancer, in particular, is more common among Black and Hispanic women and results in disproportionately higher mortality for Black women. In addition to race/ethnicity, incidence rates of penile, cervical, and vaginal cancers increase with higher poverty rates. Cervical cancer and other HPV-related cancers are preventable diseases through the 3-dose series of the HPV vaccine. Healthy People 2020 objective IID-11.4 is to increase the vaccination coverage level of 3 doses of HPV vaccine for females by age 13 to 15 years to 80%. However, HPV vaccination rates remain dramatically low in the US, particularly in underserved areas. Further, knowledge is still lacking on the correlates of HPV vaccination among underserved populations. Therefore, the purpose of this study was to examine the correlates of HPV vaccine initiation, completion, and dosing intervals for 2011-2013 among female and male adolescents in inner-city community health centers.

Methods: This is a descriptive, correlational study using electronic health records data for 6,691 adolescents seen at a multi-site community health center in 2011-2013. The study site is a federally qualified health center, providing services at seven sites in predominantly minority, low-income urban areas. Only five centers were included in this study; the two excluded centers do not provide pediatric services. The inclusion criteria were being 10-20 years old and having had at least one pediatric, OB/GYN, internal medicine, or nurse visit in 2011-2013. In the study sample, 59% were female; 91% were Black or Hispanic adolescents; 25% were non-English speakers; 31% were uninsured; and 69% were seen by a pediatric healthcare provider (HCP). The outcome variables are HPV vaccine initiation (receives at least one dose vs. did not receive any doses), completion of the 3-dose series (received 3 or more doses vs. received only 1-2 doses), and dosing intervals (in months). The predictor variables include gender, age, race/ethnicity, language, insurance status, and specialty of HCP. The EHR data were imported into SPSS statistical software for analysis. Bivariate and multivariate analyses were conducted to examine the associations between the study predictors and HPV vaccine initiation. The study analyses were conducted for the whole study sample as well as through subset analyses for female, male, Black, and Hispanic adolescents. For the bivariate analyses, we conducted chi-square tests for HPV vaccine initiation and completion, and t-tests for dosing intervals. Multivariate analyses included logistic regression for HPV vaccine initiation, linear regression for dosing intervals, and calculation of adjusted odds ratios (aOR) and 95% confidence intervals (CI). We also examined in the regression analyses the effect of any interactions among study predictors on HPV vaccination along with post-hoc analyses to further explore the interactions that were statistically significant.    

Results: Over half of the adolescents in the study (54%) have initiated the HPV vaccine. In the bivariate analysis, HPV vaccine initiation was associated with all the study predictors. The multivariate analysis revealed that odds of HPV vaccine initiation were higher for male versus female adolescents (aOR=1.15; 95% CI=1.02, 1.30), non-English versus English speakers (aOR=1.804; 95% CI=1.55, 2.11), and among insured versus uninsured adolescents (aOR=1.13; 95% CI=0.98, 1.30). The odds of initiation were lower among older versus younger adolescents (aOR=0.77; 95% CI=0.67, 0.88), those seen by a non-pediatric HCP versus a pediatric HCP (aOR=0.23; 95% CI=0.20, 0.27), and among Hispanic versus Black adolescents (aOR=0.69; 95% CI=0.60, 0.80). Only 27% of the adolescents in the study have completed the HPV vaccine 3-dose series. In the bivariate analysis, HPV vaccine completion was associated with all the study predictors except gender. The multivariate analysis revealed that odds of HPV vaccine completion were higher insured versus uninsured adolescents (aOR=1.45; 95% CI=1.21, 1.73) and Hispanic versus Black adolescents (aOR=1.19; 95% CI=1.01, 1.42). The odds of HPV vaccine completion were lower for adolescents seen by a non-pediatric HCP versus a pediatric HCP (aOR=0.54; 95% CI=0.43, 0.67). The mean dosing intervals were 6.6 months between dose 1 and 2 (SD=6.9) and 12.6 months between dose 1 and 3 (SD=8.7). The bivariate and multivariate analyses show that the dosing intervals were significantly longer among older adolescents and English speakers. More findings will be presented on subset analyses for female, male, Black, and Hispanic adolescents as well as for the effect of interactions among study predictors on HPV vaccination.

Conclusion: Improving HPV vaccination in low income urban areas is critical to reducing disparities in cervical and other HPV-related cancer in the US, especially among Black, Hispanic, and low-income populations. This study informs the development of targeted intervention to improve HPV vaccination among underserved populations in the US and around the globe. This study has potential for engaging in scholarly conversations with global partners regarding HPV vaccination and cancer health disparities. This study was funded by the New Jersey Health Foundation - School of Nursing’s Research Endowment.