Photo Credit: Md Saiful Islam Khan
The following is a summary of “Suppressed HIV antibody responses following exposure to antiretrovirals – evidence from PrEP randomized trials and early antiretroviral treatment initiation studies,” published in the August 2024 issue of Infectious Disease by Avelino-Silva et al.
Researchers conducted this retrospective study to characterize the suppressed viral replication and blunt antibody (Ab) responses, which reduce HIV detectability, impacting diagnosis and blood donation screening caused by exposure to antiretrovirals at or early after HIV acquisition.
They used 3 antigen (Ag)/Ab assays and 1 nucleic acid test (NAT) to analyze samples collected in pre-exposure prophylaxis (PrEP) trials (iPrEx; Partners PrEP) before infection detection by Ab-only rapid diagnostic tests (RDTs), and in early antiretroviral treatment (ART) initiation studies (RV254; SIPP).
The results revealed reactivity detected by NAT and Ag/Ab assays in samples collected up to 8 weeks before the first reactive RDT from 251 PrEP trial participants, ranged from 49-61% for active PrEP users and 27-37% for placebo. In the RV254 cohort, Ag/Ab assay reactivity was less than 100% at all time points and was lower among those who started ART earlier. Seroreversions occurred in 29% (16/55) of participants, and blood donation screening with NAT and Ag/Ab assays missed up to 36% (20/55) of RV254 participants. Ag/Ab assays successfully identified infections without evidence of reactivity waning for participants who initiated ART later.
They found that PrEP and early ART initiation can delay or reduce HIV detectability. They recommended balancing the implementation of NAT and Ag/Ab tests in PrEP/PEP programs with feasibility and public health impact while advocating for higher sensitivity tests in blood transfusion services.
Source: ijidonline.com/article/S1201-9712(24)00293-5/fulltext#seccesectitle0002
