The Internet, HIV serosorting and transmission risk among men who have sex with men, San Francisco.

In a community-based, time-location sampling survey in San Francisco, Internet-met partners were not more likely to be HIV seroconcordant among HIV-negative and HIV-positive men who have sex with men (MSM) compared with partners met at bars and dance clubs. In addition, HIV-negative MSM were more likely to have unprotected anal intercourse with potentially serodiscordant partners met on the Internet compared with those met at bars and dance clubs (adjusted OR 1.5, 95% CI 1.1-2.0, P = 0.01).