Development of Diagnostics to Differentiate HIV Infection from Vaccine Induced Seropositivity: Several years of clinical trials have revealed that some HIV vaccines can elicit long-lasting (>15 years) serological immune responses that can be confused with HIV infection in common diagnostic tests. This phenomenon is known as vaccine-induced sero-reactivity or sero-positivity (VISR/VISP). The overarching goal of this program is to support the development of new serological and nucleic acid assays that can identify HIV infection while avoiding false-positive results due to VISP, with high sensitivity and specificity.