Reduction in Human Papillomavirus Vaccine Type Prevalence Among Young Women Screened for Cervical Cancer in an Integrated US Healthcare Delivery System in 2007 and 2012-2013

Background. In the United States, human papillomavirus (HPV) vaccine is recommended for 11-or 12-year-olds, and for young adults not previously vaccinated. Early vaccine impact can be measured by reductions in vaccine-type (VT) HPV prevalence. Methods. Consecutive residual cervical specimens were retained from women aged 20-29 years at Kaiser Permanente Northwest in 2007, 2012, and 2013. HPV genotypes were determined using LI consensus polymerase chain reaction with type-specific hybridization to detect 37 types, including VT HPV (HPV type 6, 11, 16, and 18). We compared HPV prevalence in 2007 and 2012-2013, and we evaluated predictors of VT HPV and any-HPV prevalence in 2012-2013. Results. In 2012-2013,31.9% of 4181 women had initiated HPV vaccination. VT HPV prevalence decreased from 10.6% in 2007 to 6.2% in 2012-2013 (P < .001). In 2012-2013, VT HPV prevalence was significantly lower among those who initiated vaccination < 19 years (adjusted prevalence ratio, 0.1; 95% confidence interval, .1-. 3) than among those who were not vaccinated, and higher among those who had chlamydia, human immunodeficiency virus, or pregnancy testing in the past year than among those who did not (adjusted prevalence ratio, 1.4; 95% confidence interval, 1.1-1.8). Conclusions. Reduction in VT HPV was found in young women in an integrated healthcare delivery system within 6 years of vaccine introduction, indicating early HPV vaccine impact.