Specific Aim 3: Quantify the long-term population-level impacts of voluntary behavior change by men with recent HIV infection, through the use of dynamic mathematical modeling that integrates our data on behavior change with current estimates of temporal infectiousness patterns. The investigators will also determine whether more frequent testing and/or development of tests with earlier sensitivity may have a significant impact on the epidemic. Finally, the magnitude of this effect to that obtained by decreasing drug use or risky sexual behavior prior to or following seroconversion will be compared. This will be conducted as a statistical analysis by co-investigators at the University of Washington.