Background: To assess the impact of condom use on HIV and HSV-2 serostatus at the population and individual levels among 18- to 24-year-old men in a township of South Africa. The second objective was to identify predictors of comdom use in non-spousal partnerships. Methods: In this cross-sectional study, data were collected on background characteristics, sexual behavior and condom use. Participants were tested for HIV and HSV2 serostatus. A consistent condom user was defined as a participant who reported always using condoms with all non-spousal partners in the past 12 months. Logistic regression was used for multivariate analyses. Results: The study included 2830 men. Among those who had had at least one non-spousal partner in the past 12 months, 37.5% (95%CI: 35.4%-39.6%) used condoms consistently. Among non-spousal partnerships, 55.4% (95%CI: 53.2%-57.6%) were always protected by condoms. Non-spousal partnerships were more frequently reported as always protected by condoms when male partners had more than 4 lifetime sex partners (56.9% vs 52.7%, adjusted odds-ratio, aOR = 1.44 P = 0.003), when male partners had used a condom at first sex (74.1% vs 53.5%, aOR = 2.93 P<0.001). Among participants who had had at least one non-spousal partner in the past 12 months, those who reported consistent condom use were 2 to 3 times less infected with HIV (2.6% vs 6.1%, aOR = 0.55 (0.33-0.92) P = 0.0023) and HSV-2 (4.4% vs 10.2% aOR = 0.49 (0.33-0.73) P = 0.001) than those who inconsistently or never used condoms. The conservative estimates of the proportion of HIV and HSV-2 serostatus prevented by condom use were 14.3% (95CI: 2.4%-22.0%) and 16.5% (95%CI: 9.6%-24.6%), respectively. Conclusions: Condom use is reaching substantial levels among young men and has a clear protective effect at the individual and population levels against HIV and HSV-2. Condom use must be promoted further.
