When primary prevention for HIV infection is less than 100% effective, secondary prevention should incorporate undiagnosed HIV-positive individuals into counseling, testing, and treatment programs to reduce transmission to partners. Primary HIV infection (PHI) is the earliest period to detect HIV infection, and, if it accounts for the majority of transmission, increasing recognition of PHI could have the greatest impact on limiting the spread of the HIV epidemic. In Aim #1, we propose to implement a public health campaign to teach the symptoms of PHI to high-risk individuals and to instruct them to seek testing at selected sites if they develop those symptoms. Surveys will ascertain whether the target population saw the campaign, learned the content, and whether that learning was sustained. We will compare, by Poisson and time series analysis, the number of individuals diagnosed with PHI by public health testing before and after the educational campaign. A cost-effectiveness analysis will assess the cost of the program per individual diagnosed with PHI. Finally, we hypothesize that an increase in referrals to the Seattle Primary Infection Clinic (PIC) will provide further evidence of the benefit of the educational campaign on recognition of PHI. Aim #2, the PIC Partners Study, is part of a larger collaboration that has enrolled over 260 individuals with PHI into research studies over the last 12 years. Partners of new PIC enrollees will be screened for HIV infection and will complete a clinical and behavioral questionnaire. Transmitting (source) partners will be confirmed by viral sequencing, and a case-control study will be performed to quantify the odds of transmission associated with seminal plasma viremia in transmitting (case) versus non-transmitting (control) HIV-positive partners. These PHI projects will address novel issues related to recognition of incident infection, partnership factors contributing to transmission and acquisition, and program assessment. In the process, this award will provide learning opportunities and career development for the Principal Investigator in public health education methodology, cost-effectiveness and statistical analysis, and clinical research.