Epidemiology and natural history of human papillomavirus around the time of sexual debut

Human papillomavirus (HPV) is a sexually transmitted virus associated with cervical cancer. The East African region has one of the highest incidences and mortality rates from cervical cancer but limited studies on HPV are available. Research aims were to describe: HPV genotypes, risk factors and rate of acquisition of prevalent and incident HPV in girls before and after reported first sex; rate and risk factors associated with HPV clearance, and to examine sexual behaviour reporting in face-­‐to-­‐face (FtF) interviews compared to Audio Computer-­‐Assisted Self-­‐Interviews (ACASI). A total of 503 girls aged 15 and 16 years in Mwanza, Tanzania, were enrolled and followed 3-­‐ monthly for 18 months with FtF-­‐interviews and self-­‐administered vaginal swabs. At enrolment, 474 girls reported no previous sex, and HPV was detected in 40/474(8.4%). During follow-­‐up of girls who reported sex, new HPV incidence was 225/100 person-­‐years(pys). Reporting sex in the past 3 months, and knowing the most recent sexual partner for a longer period before sex were associated with HPV acquisition. Median time from reported sexual debut to first HPV infection was 5 months, and median duration of infection 6 months. No factors were associated with HPV clearance. In girls who reported not having sex, HPV incidence was 29.4/100pys. ACASI was compared to FtF-­‐interview in 203 girls at the 12-­‐month visit. Although ACASI was feasible and acceptable, there was no increase in reporting of sex or other sexual behaviours, with the exception of kissing, compared to FtF-­‐interviews. A very high incidence of HPV was seen in girls following sexual debut, and a higher than expected HPV prevalence and incidence were seen in girls who reported no previous sex. This emphasises the importance of HPV vaccination well before sexual debut. ACASI did not lead to increased reporting of vaginal sex and should be evaluated further in different settings.