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 f