Disparities in human papillomavirus vaccine completion among vaccine initiators.

Objective: To estimate rates of completing the full three-dose prophylactic human papillomavirus (HPV) vaccination regimen in patients who initiated the series and to identify variables associated with not completing vaccination.

Methods: This single-institution review identified all patients initiating HPV vaccination at one of four affiliated clinics between January 2007 and June 2008. Vaccination "completers" were defined as patients who had completed all three vaccinations within 12 months of initiating the vaccination series. Logistic regression was used to identify factors associated with vaccine completion. Variables analyzed included age, type of insurance (private compared with public), practice location (urban compared with suburban), practice type (pediatrics, gynecology, or family practice), and race or ethnicity (white or African American and Hispanic).

Results: Of the 1,413 girls and young women who initiated HPV vaccination, 469 (33.2%) completed the vaccine series. Overall, private insurances (odds ratio 1.87, 95% confidence interval 1.26-2.76) and suburban practice locations (odds ratio 1.44, 95% confidence interval 1.04-1.98) were associated with higher vaccine completion rates. African American race was associated with lower completion rates (odds ratio 0.50, 95% confidence interval 0.38-0.65). In multivariable analyses, the combination of younger age (11-17 years) and urban practice location was associated with very low likelihood of completing HPV vaccination (22%; P=.023).

Conclusion: The HPV vaccine completion rate is low. When resources are limited, disparities in HPV vaccine completion should be considered when developing programs to improve vaccine utilization. Urban girls and young women should be targeted as an at-risk population.