Seroconversion, seroreversion, and serowaffling among participants initiating antiretroviral therapy in Project DETECT.

Background: Incomplete HIV seroconversion and seroreversion are increasingly documented by testing and pre-exposure prophylaxis programs more than previously recognized. This analysis reports on incomplete seroconversion and seroreversion by specimen and test type among Project DETECT participants.

Methods: Project DETECT included a longitudinal study of point-of-care tests. Participants were categorized as having "incomplete seroconversion" if all timepoints had ≥1 nonreactive test at study censoring. Among participants with incomplete seroconversion, we defined "seroreversion" as sustained regression to nonreactive for any test following a reactive result. We define "serowaffling" as any reactive result followed by a nonreactive and then reactive result. We used Fisher's exact tests to explore relationships between Fiebig stage at ART initiation and incomplete seroconversion, seroreversion, and serowaffling.

Results: Twenty of 1940 Project DETECT participants met criteria for this subset. Ten participants had complete seroconversion after a median of 23 (IQR 16-47) days following initial positive tests. Ten participants had incomplete seroconversion, eight of whom had seroreversion. Incomplete seroconversion with persistent nonreactive tests was seen only with oral fluid (OF). Of eight participants with seroreversion, all experienced seroreversion of OF tests if the test was ever reactive ( = 6); seroreversion occurred in fingerstick and venipuncture tests in two participants. Serowaffling occurred in nine (45%) participants. No associations were seen between Fiebig stage at ART start and complete seroconversion, seroregression, or serowaffling in our sample.

Conclusions: OF tests may be particularly susceptible to providing false-negative results. Seroreversion and incomplete seroconversion among individuals on antiretroviral treatment may represent a growing problem for HIV testing and treatment programs.