Prevalence, incidence, and distribution of human papillomavirus types in female sex workers in Kenya

Female sex workers (FSWs) have a notably high risk of acquiring human papillomavirus (HPV) infections. Relatively few studies address the type-specific prevalence and incidence of HPV among FSWs in sub-Saharan Africa. FSWs (n = 348) attending the Korogocho clinic in Nairobi, Kenya participated from August 2009 to March 2011. HPV DNA was detected using the SPF10-LiPA25 PCR assay. Baseline prevalence of HPV infection and cervical dysplasia were calculated, stratified by HIV-serostatus. Incidence rate (IR) of infection was calculated as number of new infections from baseline over person-months among 160 HPV-negative participants with complete 12-month follow-up. Baseline HPV prevalence was 23.6% for any HPV and 20.4% for high-risk HPV (hrHPV) types. Most prevalent types were HPV52 (10.1%), HPV35 (2.3%), and HPV51 (2.3%). A quarter (24%) of participants were HIV-positive. HPV prevalence was higher in HIV-positive (32.1%) than HIV-negative (20.8%) participants. hrHPV prevalence was higher in HIV-positive (27.4%) than HIV-negative (18.2%) women. During follow-up, HPV IR was 31.4 (95% CI: 23.8–41.5) for any HPV and 24.2 (95% CI: 17.9–32.8) for hrHPV types. HPV52 had the highest IR (6.0; 95% CI: 6.5–10.3). Overall HPV and hrHPV prevalence were lower than expected, but both prevalence and incidence were higher in HIV-positive than in HIV-negative women.