Pre-vaccination prevalence of human papillomavirus types in the genital tract of 15-23-year-old women attending a youth health clinic in Stockholm, Sweden.

Knowledge of the prevalence of different human papillomavirus (HPV) types in young girls is important for the early detection of changes in HPV prevalence, e.g. due to HPV vaccines. The purpose of this study was to obtain information on the prevalence of 24 different genital HPV types in a group of sexually active young women (aged 15-23 y) attending a major youth healthcare centre in Stockholm, before the introduction of public HPV vaccination of young women in the autumn of 2010. A total of 615 women were analyzed for 24 different, mainly high-risk HPV (HR-HPV) types using multiplex polymerase chain reaction and Luminex technology. A high HPV prevalence in this cohort was demonstrated, particularly with regard to HPV16, but also to all included HR-HPV types. Of the 544 successfully analyzed samples from non-vaccinated individuals, 70% were positive for the HPV types assayed for, and 62% were positive for HR-HPV types. Over a third (34.7%) of the women were infected with HPV16, and a high frequency of infections with HR-HPV types 51 (10.7%), 18 (10.1%), 52 (9.9%) and 73 (9.4%) was also observed. At least 9 different non-vaccine HR-HPV types were present with a prevalence of >6% in this selected group of young women.