1. Pre-amble: The promises and pitfalls of using assays for recent infection to estimate HIV incidence Denis Nash, PhD, MPH Associate Professor Epidemiology and Biostatistics Program Hunter College School of Public Health SED Core, HIV Center for Clinical and Behavioral Studies

2. HIV status unknown A prospective study of HIV incidence Recruitment

3. A prospective study of HIV incidence HIV negative HIV positive HIV testing Recruitment

4. A prospective study of HIV incidence 6 months Baseline HIV positive (excluded) Prospective follow-up Enrollment of HIV negatives Prospective follow-up HIV negative (study participants) HIV testing Recruitment Seroconverted Did not seroconvert

5. 6 months Baseline HIV positive (excluded) Did not seroconvert Prospective follow-up Seroconverted Person-time Incidence rate = Calculation of HIV incidence A prospective study of HIV incidence Enrollment of HIV negatives Prospective follow-up HIV testing Recruitment

6. A cross-sectional study of HIV incidence (STARHS) HIV status unknown Recruitment 6 months Baseline Retrospective follow-up

7. 1. Identification of HIV-positive persons via conventional HIV testing A cross-sectional study of HIV incidence (STARHS) 2. Additional testing of HIV positives by recent Infection assay Seroconverted in last 6 months Seroconverted >6 months ago 6 months Baseline Retrospective follow-up

8. HIV-negative Seroconverted in last 6 months Seroconverted >6 months ago Person-time Incidence rate = A cross-sectional study of HIV incidence (STARHS) Calculation of HIV incidence Excluded 6 months Baseline Retrospective follow-up

9. Person-time Incidence rate = Seroconverted >6 months ago (excluded) Seroconverted in last 6 months HIV- negative Person-time Baseline 6 months Incidence rate = HIV positive (excluded) Prospective follow-up Did not seroconvert Seroconverted Prospective studySTARHS (cross-sectional) Baseline 6 months Prospective follow-up