Cancer 2012 04 27118(22) 5623-9 doi 10.1002/cncr.27598

Abstract
BACKGROUND
Completion of the human papillomavirus (HPV) vaccine in a large percentage of young females is an important goal to prevent anogenital cancers associated with HPV. The current study examined whether the percentage of insured women who complete the vaccine series has changed across time, and how provider type and age at initiation affects rates of completion.

METHODS
This retrospective cohort study used administrative data from a private insurance company. The study included 271,976 females in whom the HPV vaccine series was initiated and who had been continuously enrolled in their respective insurance plan for 365 days after vaccine initiation. Multivariate logistic regression was used to determine the odds of completing the vaccine series within 365 days after initiation.

RESULTS
Females aged 13 years to 18 years, 19 years to 26 years, and ≥ 27 years were found to be less likely than those ages 9 years to 12 years to complete their HPV vaccine series. Obstetricians/gynecologists were more likely to administer vaccines to completers than pediatricians, whereas clinics, nurses, family care practitioners, and specialists were less likely to administer initial vaccines to completers compared with pediatricians. The results of the current study also found that females aged 9 years to 12 years and 13 years to 18 years had lower odds of completing the HPV vaccine series for each subsequent year compared with those aged 19 years to 26 years and ≥ 27 years.

CONCLUSIONS
Among insured females in the United States, the percentage of females who complete the HPV vaccine series is dropping over time, especially among younger females, who are specifically targeted to receive the vaccine. Physicians need to stress the importance of completing all 3 vaccinations to their patients.

Author