Researchers from Boston University School of Public Health and School of Medicine conducted a cross-sectional study of 235 women age 21 to 30 undergoing routine cervical cytology testing. HPV status and demographic and behavioral characteristics were self-reported and verified with electronic medical records.
“Although data clearly indicate better immune responses and vaccine efficacy against both genital warts and cervical dysplasia when vaccination occurs before age 14, this study suggests that HPV vaccination may be effective in reducing abnormal Pap test results even after sexual debut,” explained co-author Rebecca Perkins, MD, MSc, assistant professor of Obstetrics and Gynecology at Boston University School of Medicine and a gynecologist at Boston Medical Center.
At the time of the study, 41 percent had received at least one HPV vaccination; 97 percent of women were vaccinated after sexual debut. Ten percent of women had an abnormal cervical cytology result. The prevalence of abnormal cytology was 65 percent lower in women who received at least one HPV vaccination as compared to unvaccinated women.
According to the researchers continued surveillance of HPV vaccination is necessary to identify clinical benefits, particularly given the low rate of vaccine uptake and completion and vaccination of many young women after sexual debut. “Studies should continue to compare vaccine effectiveness before and after sexual debut and by vaccine doses received and to explore the role of herd immunity,” added Perkins.
source : http://www.sciencedaily.com/releases/2014/07/140724144314.htm