The authors were interested in the relative importance of hand-to-genital and genital-to-genital transmission of human papillomavirus (HPV) between sexual partners. They conducted a prospective cohort study in which female university students aged 18-24 years and their male sexual partners in Montreal, Canada were followed-up for up to 2 years. Participants were eligible if they had initiated sexual activity within the past 6 months. Women were examined at baseline and every 4-6 months for up to 24 months. Men had a baseline visit and a single follow-up visit approximately 4 months later. Partners provided hand and genital swab samples, which we tested for the DNA of 36 HPV types. 264 women and 291 men had valid hand samples. The hazard ratio (HR) of detecting HPV in genital samples from women was 5·0 (95%CI 1·5-16·4) when her partner was positive for the same HPV type on his hand, but adjustment for his genital HPV status reduced the HR to 0·5 (95%CI 0·1-1·8). The HR of HPV on men’s genitals was 17·4 (95%CI 7·9-38·5) when his partner was positive for the same HPV type on her hand but again adjustment for her genital HPV status reduced the HR to 2·3 (95%CI 0·9-6·2). Conversely, the HR of type-specific detection of HPV in genital samples associated with partner genital HPV positivity was 19·3 (95%CI 11·8-31·8) for women and 28·4 (95%CI 15·4-52·1) for men after adjusting for their hand HPV status. Therefore HPV transmission is unlikely to occur through hand-to-genital contact, with the majority caused by genital-to-genital sexual transmission.
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