Concurrent sexual partnerships among young heterosexual adults at increased HIV risk: types and characteristics.

BACKGROUND: The impact of concurrency on sexually transmitted infection transmission depends on coital frequency, condom use, duration of relationship overlap, and number of partners. Previous research has identified distinct concurrency types; however, little is known about their risk characteristics. METHODS: Men (n = 261) and women (n = 275) aged 18 to 30 years at increased risk for acquiring HIV were recruited from community locations in Los Angeles. Participants completed 4 in-person interviews for 12 months. Partnership data were used to characterize the prevalence of 4 types of concurrency: transitional (2 overlapping relationships in which the first relationship ended before the second), single day (a second relationship of 1 day's duration during the course of another relationship), contained (a second relationship >1 day began and ended during the course of another), and multiple (≥3 overlapping relationships). Multilevel random intercept models were used to estimate mean coital frequency, proportion of condom-protected acts, total duration of overlap, and lifetime sex partners. RESULTS: At baseline, 47% of male and 32% of female participants reported any type of concurrency in the previous 4 months, and 26% of men and 10% of women reported multiple concurrencies. Condom use ranged from 56% to 64%, with the highest use in transitional concurrency (61% for men, 68% for women) and the lowest in contained (52% for men, 54% for women). Coital frequency, total overlap, and lifetime sex partners also varied by concurrency type. CONCLUSIONS: Inconsistent condom use and repeated opportunities for exposure characterize common types of concurrency among high-risk young adults.

Time for change? An economic evaluation of integrated cervical screening and HPV immunization programs in Canada.

Many jurisdictions have implemented universal human papillomavirus (HPV) immunization programs in preadolescent females. However, the cost-effectiveness of modified cervical screening guidelines and/or catch-up immunization in older females in Canada has not been evaluated. We conducted a cost-utility analysis of screening and immunization with the bivalent vaccine for the Canadian setting from the Ministry of Health perspective. We used a dynamic model to capture herd immunity and included cross-protection against strains not included in the vaccine. We found that adding catch-up immunization to the current program would be cost-effective, and that combining catch-up immunization with delaying the age at which screening is first initiated could result in cost savings and net health gains.