Vaccine
http://www.sciencedirect.com/science/journal/0264410X
Volume 30, Issue 37 pp. 5449-5584 (10 August 2012)

Reduction of HPV infections through vaccination among at-risk urban adolescents
Original Research Article
Pages 5496-5499
Teresa Cummings, Gregory D. Zimet, Darron Brown, Wanzhu Tu, Ziyi Yang, J. Dennis Fortenberry, Marcia L. Shew

Abstract
Introduction
Human papillomavirus (HPV) vaccine trials have demonstrated high efficacy in preventing HPV infections and HPV related disease in females ages 16–26. However, there is no source data to demonstrate the impact of the vaccine in other populations who may be at higher risk for HPV related disease. This study examines the impact of HPV vaccination on subsequent HPV detection and sexual behaviors among urban adolescents in a clinical setting.

Methods
A cohort of adolescent women, ages 14–17, were recruited prospectively and matched to historical controls to assess the impact of HPV vaccination. All women completed the same questionnaire and face-to-face interview that assessed sexual behaviors; all provided a clinician or self-collected vaginal swab that was used to test for sexually transmitted infections, including HPV. Logistic regression models, incorporating random pair effects, were used to assess the impact of the HPV vaccine on HPV detection and sexual behaviors between the two groups.

Results
Each woman recruited (N = 75) was matched to 2 historical controls (HC); most of the recruited women (89.3%) had received one or more doses of the HPV vaccine. At enrollment, detection of quadrivalent vaccine types (HPV 6, 11, 16 and 18) was significantly less in the recruited group (5.3%) as compared to the HC (24%): OR = 5.6 (CI = 1.9, 16.5), p = 0.002. Adolescent women in the HC had a 9.5 times greater odds of HPV infection when the analysis was adjusted to compare those who had 2 or more vaccine doses to their matched controls. The only behavioral difference found was that the recruited women used condoms more frequently.

Conclusion
This study demonstrates that HPV vaccination was associated with fewer vaccine-type HPV infections despite incomplete vaccination and high risk sexual behaviors. These data also suggest that sexual behaviors were not altered because of the vaccine.