A new study conducted by the Thai Red Cross and the U.S. Military HIV Research Program (MHRP) has shown that detecting HIV during acute infection and immediately initiating antiretroviral therapy (ART) was associated with an estimated 89% reduction in HIV transmission in a Thai cohort compared to those who receive no intervention during acute infection. Findings from the study were published last week in the Journal of the International AIDS Society.
Acute HIV infection (AHI) is characterized by high viral replication and increased infectiousness. Though ART reduces HIV transmission, incidence of infection is still high in some regions among populations of men who have sex with men (MSM).
“Post-diagnosis behavioral changes can significantly reduce the number of new HIV infections, but viral load reductions through ART have the greatest impact,” said Dr. Jintanat Ananworanich, MHRP’s Associate Director for Therapeutics Research and coauthor of the paper.
Study volunteers were drawn from RV254/SEARCH 010, a prospective cohort study conducted in Bangkok, Thailand. The study enrolls predominantly Thai participants in the earliest stages of AHI, usually within weeks of infection, and immediately starts them on ART.
In the new follow-on study, a risk calculator based on viral load and reported behavior was applied to estimate the number of onwards transmissions in the Thai cohort. This was compared with the expected number of transmissions that could be estimated to have occurred without early intervention.
The estimated number of onwards transmissions per infected individual during the first year of infection would have been 27.3 with no intervention, 8.3 with post-diagnosis behavior change only, and 5.9 transmissions with viral load reduction only. With both behavior change and viral load reduction due to early ART initiation, the estimated transmissions per infected individual were lowest at 3.1. This represents an almost 89% reduction in HIV transmission.
This modeling study confirms the importance of early treatment. “We believe that global targets that aim to eliminate HIV by 2030 require investment in prioritizing detection and treatment of early HIV infection,” said Ananworanich.