Detection and Clearance of Type-Specific and Phylogenetically Related Genital Human Papillomavirus Infections in Young Women in New Heterosexual Relationships.

BACKGROUND: Understanding the natural history of human papillomavirus (HPV) infections is essential to cervical cancer prevention planning. We estimated HPV type-specific infection detection and clearance in young women. METHODS: The HPV Infection and Transmission among Couples through Heterosexual activity (HITCH) study is a prospective cohort of 502 college-age women who recently initiated a heterosexual relationship. We tested vaginal samples collected at 6 clinical visits over 24 months for 36 HPV types. Using rates and Kaplan-Meier analysis, we estimated time-to-event statistics with 95% confidence intervals (CIs) for detection of incident infections and clearance of incident and present-at-baseline infections (separately). We conducted analyses at the woman- and HPV-levels, with HPV types grouped by phylogenetic relatedness. RESULTS: By 24 months, we detected incident infections in 40.4% (CI, 33.4%-48.4%) of women. Incident subgenus 1 (43.4; CI, 33.6-56.4), 2 (47.1; CI, 39.9-55.5), and 3 (46.6; CI, 37.7-57.7) infections cleared at similar rates per 1000 infection-months. We observed similar homogeny in HPV-level clearance rates among present-at-baseline infections. CONCLUSIONS: Our analyses provide type-specific infection natural history estimates for cervical cancer prevention planning. HPV-level analyses did not clearly indicate that high oncogenic risk subgenus 2 infections persist longer than their low oncogenic risk subgenera 1 and 3 counterparts.

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.

Detection and clearance of type-specific and phylogenetically related genital human papillomavirus infections in young women in new heterosexual relationships.

Background: Understanding the natural history of human papillomavirus (HPV) infections is essential to effective cervical cancer prevention planning. We examined these outcomes in-depth among young women. Methods: The HPV Infection and Transmission among Couples through Heterosexual Activity (HITCH) study is a prospective cohort of 501 college-age women who recently initiated a heterosexual relationship. We tested vaginal samples collected at six clinical visits over 24 months for 36 HPV types. Using rates and Kaplan-Meier analysis, we estimated time-to-event statistics with 95% confidence intervals (CIs) for detection of incident infections and liberal clearance of incident and present-at-baseline infections (separately). We conducted analyses at the woman- and HPV-levels, with HPV types grouped by phylogenetic relatedness. Results: By 24 months, we detected incident infections in 40.4%, CI:33.4-48.4 of women. Incident subgenus 1 (43.4, CI:33.6-56.4), 2 (47.1, CI:39.9-55.5) and 3 (46.6, CI:37.7-57.7) infections cleared at similar rates per 1000 infection-months. We observed similar homogeny in HPV-level clearance rates among present-at-baseline infections. Conclusions: Our woman-level analyses of infection detection and clearance agreed with similar studies. However, our HPV-level analyses did not clearly indicate that high oncogenic risk subgenus 2 infections take longer to clear than their low oncogenic risk and commensal subgenera 1 and 3 counterparts.