Human papillomavirus prevalence and type distribution in urine samples from Norwegian women aged 17 and 21 years: A nationwide cross-sectional study of three non-vaccinated birth cohorts.

BACKGROUND:The aim of the current study was to assess the HPV prevalence in unscreened and unvaccinated young women living in Norway, to provide important baseline data for early estimation of the impact of the HPV vaccination program. METHODS:A total of 13,129 self-sampled urine samples from two complete birth-cohorts of 17-year old women born in 1994 and 1996 and one third of a birth-cohort of 21-year old women born in 1990, were analysed for the presence of 37 HPV types using PCR and a DNA hybridization technique. RESULTS:In the two birth cohorts of 17-year old women, HPV was detected in 19.9% (95% CI 18.8-20.9) and 15.4% (95% CI 14.5-16.3), respectively. High-risk HPV types were detected in 11.2% (95% CI 10.3-12.0) and 7.6% (95% CI 6.9-8.2), respectively, while vaccine types were detected in 7.4% (95% CI 6.7-8.1) and 6.0% (95% CI 5.4-6.6), respectively. Among the 21-year old women HPV was detected in 45.4% (95% CI 42.9-47.8), whereas high-risk types were detected in 29.8% (95% CI 27.5-32.0). Vaccine types (HPV 6, 11, 16, 18) were detected in 16.2% (95% CI 14.4-18.1). CONCLUSION:This large population based study confirms that HPV testing in urine samples is easy and highly feasible for epidemiological studies and vaccine surveillance in young women. HPV was very common and a broad spectrum of HPV types was identified. Differences in HPV prevalence was seen both between age groups and between the two birth cohorts of 17-year old women.