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

Abstract

BackgroundThe 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.MethodsA 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.ResultsIn 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).ConclusionThis 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.

Substantial Decline in Prevalence of Vaccine-Type and Nonvaccine-Type Human Papillomavirus (HPV) in Vaccinated and Unvaccinated Girls 5 Years After Implementing HPV Vaccine in Norway

“…As previously reported, we also observed a significant reduction in HPV prevalence in the 1996 cohort [ 12 ]. Given the large herd protection in unvaccinated girls, it seems likely that the reduction in HPV prevalence in the 1996 cohort, at least partially, is caused by herd effect, and not entirely by natural fluctuation in the occurrence of HPV.…”

“…DNA extraction and HPV genotyping were performed at the Norwegian HPV Reference Laboratory as previously described [ 12 ]. In brief, the presence of HPV DNA was investigated using a modified GP5 + /GP6 + polymerase chain reaction (PCR) protocol [ 15 ], followed by Luminex-based genotype detection [ 16 ].…”

“…Thus, screening data are not suitable to assess early vaccine impact. Consequently, a national HPV surveillance program comprising a series of nationwide, population-based cross-sectional studies was set up, assessing HPV prevalence in urine samples from girls and young women not yet targeted by the national screening program [ 12 ].…”

HPV Genotyping of Modified General Primer-Amplicons Is More Analytically Sensitive and Specific by Sequencing than by Hybridization

“…In Norway, HPV vaccination was introduced in 2009 for girls in the 7th grade, as a part of the childhood vaccination program. In order to monitor vaccine effectiveness and potential vaccine-related changes in the HPV-type epidemiology, genotyping of HPV in urine samples from vaccinated and non-vaccinated girls and young women is undertaken [9]. …”

“…Urine samples were chosen since these are investigated in the HPV vaccine surveillance program in Norway [9]. …”