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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 November 2024 issue of Infectious Disease by Avelino-Silva et al. 

Researchers conducted a retrospective study to examine how early exposure to antiretrovirals impacted viral replication and antibody (Ab) responses, potentially impacting HIV diagnosis and blood donation screening.   

They employed 3 antigen (Ag)/Ab assays and 1 nucleic acid test (NAT) to analyze samples from pre-exposure prophylaxis (PrEP) trials (iPrEx; Partners PrEP) before detection by AB-only rapid diagnostic tests (RDTs). Additionally, the samples were used from early antiretroviral treatment (ART) initiation studies, RV254; SeroIncidence Panel Project (SIPP) for the analysis.   

The results showed that reactivity using NAT and Ag/Ab assays in samples were 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 users. Among RV254 participants, Ag/Ab assay reactivity was below 100% at all time points, with lower reactivity in those starting ART. Seroreversions were observed in 29% (16/55) of participants, and blood donation screening with NAT and Ag/Ab assays could have missed up to 36% (20/55). In the SIPP cohort, who began ART later, Ag/Ab assays detected infections without evidence of waning reactivity.     

Investigators concluded that implementing higher-sensitivity HIV tests in PrEP, PEP, and blood transfusion programs should be balanced with feasibility and public health considerations, while further research was needed for testing algorithms. 

Source: sciencedirect.com/science/article/pii/S1201971224002935