Correlates for HPV Vaccine Three-Dose Regimen Completion in Adolescent Girls and Young Women in a Managed Care Organization

The quadrivalent human papillomavirus vaccine (HPV4) is recommended to be given in three injections within 12 months. Non-compliance to the regimen may adversely affect vaccine efficacy. Thus, we examined the rate and correlates of HPV4 regimen completion in the managed care population of Kaiser Permanente Southern California.

Female members age 9-26 years who received the first dose of HPV4 between 10/2006-03/2007 and maintained health plan membership 12 months afterwards were identified and followed for regimen completion. We examined (1) demographics/socioeconomic status (SES); (2) primary care provider (PCP) characteristics; (3) historical health service utilization; (4) women's health-related conditions and (5) selected immune-related conditions for their association with completion in two age groups: 9-17 and 18-26 years. Multivariable log-binomial regression was used to directly estimate relative risk (RR). Of the 34,193 females who initiated HPV4, the completion rate was 41.9% in 9-17 and 47.1% in 18-26 year olds. Black race (RR=0.70, 95% CI=0.64-0.77) and lower neighborhood education level were associated with lower regimen completion. However, girls on state subsidized program Medi-Cal were more likely to complete the regimen (RR=1.14 (1.07-1.22)). Historical hospitalizations and emergency room visits (RR=0.92 (0.88-0.97) and 0.92 (0.87-0.98) per visit, respectively) and having pediatrician PCP for young women were also predictors of incompletion. History of sexually transmitted infections/abnormal Pap test results and immune-related conditions (e.g., asthma/infections) were not associated with regimen completion.

These findings suggest that there are factors such as race or SES subgroups that could be taken into account when designing and evaluating the HPV vaccination programs.