Very High Prevalence of Virus Linked to Cervical Cancer Found in Adolescent Women

Exceeding rates observed in previous research, a new study found four out of five sexually active adolescent women infected with human papillomavirus, a virus linked to cervical cancer and genital warts. Darron R. Brown and colleagues of Indiana University School of Medicine studied 60 adolescent women, ages 14 to 17, at three primary care clinics in Indianapolis. They reported their results in the Jan. 15 issue of The Journal of Infectious Diseases, now available online.

Human papillomavirus (HPV) infection is a common sexually transmitted infection whose effects may range from asymptomatic carriage of the virus to genital warts to cervical cancer. In this study, 95 percent of the subjects 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 subjects 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 course of the study, 49 of 60 subjects 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. Clinically, 37 percent of the study participants had at least one abnormal result for cervical examination during the study period.

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 an assay that detects more HPV types than some other assays do, and to the at-risk nature of this particular study population.

Distinguished by its long follow-up and frequent testing procedures, this study confirms previous findings that HPV infection is common in sexually active adolescent women. “We hope the results of our research increase our understanding of HPV infection in this population,” said Dr. Brown, “and help others design effective interventions to prevent infection in adolescent women.”