SS 17-06ESTIMATING THE POPULATION ATTRIBUTABLE FRACTION OF ALL HPV DNA DETECTIONS DUE TO PARTNER DEPOSITION: HITCH COHORT STUDY

02. Epidemiology and natural history
T. Malagón 1, A.N. Burchell 2, M. El-Zein 1, J. Guénoun 3, P.P. Tellier 4, F. Coutlée 3, E.L. Franco 1.
11. Division of Cancer Epidemiology, Department of Oncology, McGill University, Montreal, Canada (Canada), 22. Department of Family and Community Medicine and Centre for Urban Health Solutions, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada (Canada), 33. Département de microbiologie et infectiologie, Centre Hospitalier de l’Université de Montréal, Montreal, Canada (Canada), 44. Department of Family Medicine, McGill University, Montreal, Canada (Canada)

Background / Objectives

Detection of HPV DNA in genital samples may not always reflect true infections but may reflect depositions from recent sex with infected sexual partners. We estimated the fraction of all HPV DNA detections potentially attributable to deposition using excess type-specific HPV partner concordance associated with recent vaginal sex in a population of young heterosexual couples.


Methods

Women aged 18-24 and their male partners aged ≥18 were recruited into the HITCH study during 2005-2010 in Montreal, Canada. We used PCR to test both partners’ baseline genital samples for 36 HPV types. We analyzed the cross-sectional association between number of days since last vaginal sex and type-specific HPV DNA concordance (probability both partners are HPV positive for the same type if one partner is positive) using log-linear multivariate models and GEE to account for correlations between HPV types. We calculated the population attributable fraction of HPV DNA detections associated with recent vaginal sex.


Results

Type-specific HPV concordance was 42.4% in partnerships where at least one partner was HPV DNA positive for that type. Type-specific concordance was 26.5% higher (95%CI 12.9-40.0%) between partners who last had vaginal sex 0-1 than partners who last had vaginal sex 8-14 days ago, and was 22.6% higher (95%CI 9.7-35.6%) between partners who never use condoms than between partners who always use condoms, even after adjustment for frequency of vaginal sex and cumulative number of sex acts since the start of the partnership. Partners who never used condoms had 42.1% higher type-specific concordance the day after vaginal sex than ≥4 days later. Under the assumption that the adjusted excess concordance between partners who had vaginal sex in the past week reflects deposition, we estimated that 14.1% (95%CI 6.3-21.9%) of all type-specific HPV DNA detections in our cohort were depositions due to vaginal sex in the past week.


Conclusion

A substantial proportion of HPV DNA detections may be depositions due to recent vaginal sex and lack of condom use in sexually active young adults. Condom use prevents deposition and should be recommended before HPV DNA testing and for the prevention of HPV transmission.


References