Seroprevalence and genital DNA prevalence of HPV types 6, 11, 16 and 18 in a cohort of young Norwegian women: study design and cohort characteristics.

BACKGROUND: Long-term efficacy evaluations of a quadrivalent HPV type 6/11/16/18 vaccine are ongoing in the Nordic region. As there are limited epidemiological data on HPV infection in Norway, we determined prevalence and identified sociobehavioural correlates of HPV 6/11/16/18 infection in young Norwegian women. METHODS: Norwegian (n=898) women, aged 1624 years, were enrolled in a 4-year prospective study. At enrolment and at 6-month intervals thereafter, an interview on behavioural data and a gynaecological examination were undertaken. Genital samples were tested for the L1,E6 and E7 genes of HPV-6/11/16/18, and serum anti-HPV-6/11/16/18 levels were measured using a competitive Luminex immunoassay (cLIA). Results. DNA and seroprevalence of HPV 6, 11, 16 or 18 ranged from 0.9 to 16.3% and 2.6 to 16.2%,respectively; and most infected women (approximately 75%) were infected with only 1 type. Of the HPV DNA positive cases, 54.3, 50.0,47.3 and 38.5% had detectable HPV 6, 11, 16 or 18 antibodies, respectively. More than 50% of the high-grade cervical intraepithelial neoplasia (CIN) cases were HPV-16 or HPV-18 DNA positive. Lifetime number of partners was the strongest and only predictor of sero- and DNA-positivity across the 4 HPV types. CONCLUSION: Given the high prevalence of HPV infection among young women with mostly single-type infection, and the fact that type-specific HPV screening is not recommended prior to the administration of the quadrivalent HPV vaccine, our data suggest the importance of widespread,rather than targeted, immunisation.

Optimization and validation of a multiplexed luminex assay to quantify antibodies to neutralizing epitopes on human papillomaviruses 6, 11, 16, and 18.

A human papillomavirus (HPV) multiplexed competitive Luminex immunoassay first described by Opalka et al. (D. Opalka, C. E. Lachman, S. A. MacMullen, K. U. Jansen, J. F. Smith, N. Chirmule, and M. T. Esser, Clin. Diagn. Lab. Immunol. 10:108--15, 2003) was optimized and validated for use in epidemiology studies and vaccine clinical trials. Optimization increased both the analytical sensitivity and the clinical specificity of the assay to more effectively discriminate the low-titer antibody response of HPV-infected persons from noninfected individuals. The characteristics of the assay that were optimized included monoclonal antibody (MAb) specificity, scaling up the conjugation of virus-like particles (VLPs) to microspheres, VLP concentration, MAb concentration, sample matrix, sample dilution, incubation time, heat inactivation of sample sera, and detergent effects on assay buffer. The assay was automated by use of a TECAN Genesis Workstation, thus improving assay throughput, reproducibility, and operator safety. Following optimization, the assay was validated using several distinct serum panels from individuals determined to be at low and high risk for HPV infection. The validated assay was then used to determine the clinical serostatus cutoff. This high-throughput assay has proven useful for performing epidemiology studies and evaluating the efficacy of prophylactic HPV vaccines.