Epidemiology of genital human papillomavirus infections in sequential male sex partners of young females.

OBJECTIVES: Couple-based studies have considered human papillomavirus (HPV) transmission between current heterosexual partners (male↔female). Using data from young women and their sequential male partners, we analysed HPV transmission from upstream sexual partnerships (male 1↔female) to downstream sex partners (→male 2). METHODS: Among 502 females enrolled in the HPV Infection and Transmission among Couples through Heterosexual activity study (2005-2011, Montréal, Canada), 42 brought one male sex partner at baseline (male 1) and another during follow-up (male 2). Female genital samples, collected at six visits over 24 months, and male genital samples, collected at two visits over 4 months, were tested for 36 HPV types (n = 1512 detectable infections). We calculated observed/expected ratios with 95% CIs for type-specific HPV concordance between males 1 and 2. Using mixed-effects regression, we estimated ORs with 95% CIs for male 2 testing positive for the same HPV type as male 1. RESULTS: Detection of the same HPV type in males 1 and 2 occurred 2.6 (CI 1.9-3.5) times more often than chance (29 instances observed vs. 10.95 instances expected). The OR for male 2 positivity was 4.2 (CI 2.5-7.0). Adjusting for the number of times the linking female tested positive for the same HPV type attenuated the relationship between male 1 and 2 positivity, suggesting mediation. CONCLUSIONS: High type-specific HPV concordance between males 1 and 2 confirms HPV's transmissibility in chains of sequential sexual partnerships. HPV positivity in an upstream partnership predicted positivity in a downstream male when the linking female partner was persistently positive.