Abstract Body

Antiretroviral therapy (ART) initiated during acute HIV infection (AHI) may result in HIV seronegativity. Little is known about the serologic profile following ART treatment interruption (ATI) in such individuals. Knowledge gained could inform recommendations for HIV diagnostic testing following pre- and post-exposure prophylaxis.

Participants initiating ART and virally suppressed during Fiebig (F)-I or F-III stage of AHI were enrolled in two ATI studies and resumed ART with VL > 1000 copies/ml (median duration of ATI was 4.5 weeks). HIV serostatus was determined pre- (median [range]:122.6 wks [5.0-285.1]) and post-ATI; median:5.3 wks [0.4-53.9]), using Avioq HIV Microelisa (AVQ, 2ndG IA), Genscreen HIV-1/2 (GSC, 3rdG IA), Architect HIV Ag/Ab Combo (ARC, 4thG IA), Determine HIV-1/2 (DET, RDT), SD Bioline HIV-1/2 3.0 (BIO, RDT) and Serodia HIV (SRD, RDT), all of which are widely used in Thailand: ARC 35%, DET 62%, BIO 32% and SRD 14% of laboratories (N=264) surveyed.

Participants (N=8) initiating ART during F-I AHI were frequently HIV seronegative pre-ATI by AVQ (88%), followed by ARC, BIO, DET (75%), and GSC and SRD (38%). The frequency of seropositivity following ATI varied for participants (75%-88%) depending on the test (Table 1). One participant was HIV seronegative throughout the study by ARC only while another showed non-reactivity to all tests throughout the study. Eighty % of participants initiating ART during F-III AHI (N=5) were HIV seronegative pre-ATI by BIO and 40% by ARC, AVQ and DET. All participants were seropositive pre-ATI by GSC and SRD. All participants were seropositive post ATI for all tests. Pre-ATI HIV seronegative frequencies ranged from 23%-69% for kits using viral lysate (AVQ, SRD), and 23-77% for kit using Env and Gag (GSC, BIO) as AG. Increased HIV seronegative frequencies (62%) pre-ATI was observed with test kits employing HIV Env (gp41) as the detecting AG (ARC, DET). Similar HIV seropositive frequencies following ATI were detected with all tests (85%-92%).

HIV serology may remain negative following early ART initiation, particularly in Fiebig I, with frequencies differing by tests. However, the majority of participants who underwent short ATI became HIV seropositive on almost all tests.