Four out of five sexually active adolescent females infected with the human papillomavirus

More sexually active adolescent females than previously thought may be infected with a virus linked to cervical cancer and genital warts, according to a study published in the Jan. 15 issue of The Journal of Infectious Diseases.

The research, reported by Darron R. Brown, M.D., and colleagues at the Indiana University School of Medicine, found four out of five sexually active adolescent females infected with the human papillomavirus. The study said the rates observed among the 60 study participants from three primary care clinics in Indianapolis exceeded the HPV rates reported in previous research.

Human papillomavirus is a common sexually transmitted infection and its effects may range from no symptoms to genital warts to cervical cancer.

In the current study, 95 percent of the participants, ages 14 to 17 years, were sexually active, and the median number of sexual partners was two. Eighty-five percent were African American, 11 percent were Caucasian and 3 percent were Hispanic.

Participation in the study involved quarterly visits to a primary care clinic for a cervical swab test and up to five 3-month diary collection periods, during which the adolescents recorded their sexual behavior daily and performed self-vaginal swabbing weekly. Each woman participated in the study for an average of two years. Brown and colleagues collected a total of about 2,100 swab specimens adequate for analysis of HPV infection.

During the study, 49 of 60 participants tested positive for HPV infection. In addition to an 82 percent prevalence rate, the investigators identified several characteristics of the HPV infections detected.

Many of the HPV-positive study participants were infected with not just one, but multiple, HPV types. The mean number of types per participant was about five. Among these different types, a substantial number were those associated with an increased risk for cervical cancer: 39 percent of the swab specimens were classified as high-risk types and 20 percent as low-risk. Thirty-seven percent of the study participants had at least one abnormal result for cervical examination during the study period.

Dr. Brown and colleagues hypothesized that relative to earlier research, the high cumulative prevalence of HPV infection in their study was primarily a result of the high number of swab specimens obtained from each study participant. Many infections were detectable for only a few weeks and might have been missed had specimens been obtained at longer intervals of time.

They also attributed the high prevalence to their use of a test that detects more HPV types than some other tests do, and to the at-risk nature of this particular study population.

"We hope the results of our research increase our understanding of HPV infection in this population and help others design effective interventions to prevent infection in adolescent women," said Dr. Brown.