Minority women who received the Human Papillomavirus Vaccination (HPV) after they had already become sexually active still had lower rates of abnormal Pap tests than those who had not gotten the shots at all. 

The findings were published in a recent edition of the journal Sexually Transmitted Diseases, Boston University Medical Center reported.

Researchers from the Boston University School of Public Health and School of Medicine conducted a cross-sectional study of 235 women between the ages of 21 and 30 who underwent  routine cervical cytology testing. In the study behavioral tendencies were self-reported and electronic medical records were reviewed by the researchers. 

"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.

When the study was performed 41 percent of the participants had received at least one dose of the HPV vaccine. Ninety-seven of the women who had been vaccinated had gotten the shots after they were already sexually active. Ten percent of the study participants received an abnormal cervical cytology result; the prevalence of these abnormal test results were 65 percent lower in women who received at least one HPV shot compared with those who had never received one. 

The researchers believe it is important to keep monitoring the HPV vaccine so its benefits can be more-easily demonstrated to women who have not received it. 

"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," Perkins said. 

Funding for this study was provided by the American Cancer Society.