HIV Antibody Increases Following Viral Rebound in People Receiving Antiretroviral Therapy

The purpose of this study is to establish a proof-of-concept for whether rapid test can detect viral rebounds that occurred within a retrospective time window among PLHIV receiving ART in the United States and sub-Saharan Africa. The objective of this study is to assess whether HIV antibody levels rise following HIV viral rebound, and the sensitivity and specificity of antibody level increases for detecting HIV viral rebounds. The investigators will conduct a retrospective matched case-control study of individuals with or without suppressed viral load on antiretroviral therapy (ART). Biobanked specimens will be tested for antibody levels.

Inclusion Criteria: * HIV-positive individuals aged 15 or older at the time of ART initiation. * Participated in HIV plasma or serum biobanking and viral load testing, with three samples after January 1, 2015 as follows: * T1 specimen with suppressed VL and sufficient sample to conduct antibody testing. * T2 specimen collected 1-13 months after T1, with: Cases: unsuppressed VL; Controls: suppressed VL. * T3 specimen collected 1-13 months after T2, with sufficient sample to conduct antibody testing. * At least one VL measurement recorded prior to T1, with: * All VL measurements made in the year prior to T1 showing suppressed VL. * If no VL measurements were made in the year prior to T1, the most recent VL measurement made prior to T1 showing suppressed VL. Exclusion Criteria: * Individuals with advanced HIV disease from 1 year prior to T1 until T3, defined as: * CD4 cell count \