Abstract 844: Comparison of HPV prevalence between HPV-vaccinated and non-vaccinated young adult women (20-26 years)
Authors: Guo Fangjian , Hirth Jacqueline M. , Berenson Abbey B. 
Published: August 2015

Background Although the HPV vaccine provides protection against genital warts and HPV-associated anogenital cancers among young girls, there is some concern about its effectiveness when administered to young adult women due to the risk of prior HPV infections before vaccination and potentially reduced immunogenicity when administered at older ages. This study used 2 cycles of the National Health and Nutrition Examination Survey (NHANES) data to evaluate the effectiveness of the HPV vaccine among women 20-26 years of age.

Methods This cross-sectional study included 592 young adult women (20-26 years) with complete information on HPV prevalence and HPV vaccination status from NHANES 2007-2010. Multivariate logistic regression models were used to examine differences in HPV prevalence between vaccinated and unvaccinated young women.

Results After controlling for past sexual behaviors, vaccinated women had a lower risk of testing positive for the 4 types included in the HPV vaccine (6, 11, 16, or 18; Table 1). This association became stronger when the number of recent sexual partners was controlled for. However, vaccinated women had a higher prevalence of nonvaccine high-risk types than unvaccinated women (61.5% vs 39.7%, prevalence ratio 1.55, 95% CI 1.22-1.98). After adjusting for the number of recent sexual partners, the difference in prevalence of high-risk nonvaccine types was reduced, but remained significant.

Conclusion HPV vaccination was effective for the protection against all four vaccine types in young adult women. Vaccinated women had a higher prevalence of nonvaccine high-risk types, which suggests that they may benefit from vaccines that cover additional types of HPV.

Table 1. Type-specific HPV prevalence among US adult women by HPV vaccination status.

Prevalence (95% CI)aPrevalence Ratio (95% CI)Adjusted Prevalence Ratio (95% CI) Vaccinated vs. UnvaccinatedVaccinated (n = 80)Unvaccinated (n = 512)Model 1bModel 2cModel 3dAny HPV70.7 (59.1-82.3)56.1 (50.2-62.0)1.26(1.05-1.52)1.28(1.05-1.55)1.24(1.02-1.52)1.21(0.99-1.48)Low-Risk Type41.6 (30.4-52.8)40.3 (34.0-46.5)1.03(0.77-1.38)1.06(0.76-1.47)1.03(0.72-1.45)0.96(0.68-1.37)High-Risk Type63.6 (51.4-75.7)44.5 (39.1-49.9)1.43(1.14-1.79)1.34(1.07-1.69)1.30(1.06-1.60)1.26(1.03-1.53)HPV 6, 11, 16 or 1810.8 (2.2-19.4)19.7 (15.8-23.7)0.55(0.26-1.15)0.48(0.23-1.01)0.46(0.22-0.93)0.42(0.21-0.87)HPV 6 or 1105.6 (3.5-7.7)0HPV 16 or 1810.8 (2.2-19.4)15.9 (12.1-19.7)0.68(0.32-1.45)0.57(0.27-1.21)0.54(0.26-1.12)0.51(0.25-1.04)Nonvaccine Type68.6 (57.1-80.2)53.9 (47.9-60.0)1.27(1.05-1.54)1.28(1.05-1.57)1.25(1.02-1.54)1.21(0.98-1.48)Nonvaccine Low-Risk Type41.6 (30.4-52.8)38.1 (31.9-44.4)1.09(0.81-1.46)1.11(0.79-1.56)1.08(0.76-1.55)1.02(0.71-1.47)Nonvaccine High-Risk Type61.5 (49.4-73.7)39.7 (34.7-44.7)1.55(1.22-1.98)1.47(1.15-1.88)1.43(1.14-1.79)1.38(1.11-1.71)aPrevalence was weighted using sample weights.bModel 1 was adjusted for age, race/ethnicity, education, income, smoking status, and marital status.cModel 2 was adjusted for variables in Model 1 plus sexually transmitted diseases and number of lifetime sexual partners.dModel 3 was adjusted for variables in Model 2 plus number of sexual partners in the past 12 months.

Citation Format: Fangjian Guo, Jacqueline M. Hirth, Abbey B. Berenson. Comparison of HPV prevalence between HPV-vaccinated and non-vaccinated young adult women (20-26 years). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 844. doi:10.1158/1538-7445.AM2015-844