Clinical posts from members and guests of the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM) from various international medical and scientific conferences on HIV, AIDS, viral hepatitis, and sexual health.
Treatment to prevent HIV - Does timing matter?
In this plenary session, Professor Myron S Cohen presented summary of the HPTN 052 study. This study assesses the risk of HIV transmission in couples where the HIV positive partner is either treated early, compared to couples where the treatment of the positive partner is delayed. Contrary to some medical media reports, the HPTN 052 study is ongoing, in 2015 some 1535 participants remain enrolled, and over 9000 years of follow-up have been completed. Participants are allowed to bring new partners into the study.
Prof Cohen reported an overall 93% reduction in the risk of transmission in those couples where the positive partner was started on ART early versus the risk in those couples where ART treatment was delayed. However, Prof Cohen stated that the actual risk reduction is probably closer to 100%, based on the following analysis of linked transmissions:
- In total 8 linked infections occurred after the index started ART
- 4 were diagnosed soon after the index started ART, raising the possibility that these transmission occurred before the index attained virologic suppression.
- 4 occurred after the index failed ART
- No infections were observed when HIV replication was suppressed.
Prof Cohen also shared his thoughts on starting ART during primary HIV infection (PHI), at the time of diagnosis. He argued that people should start ART immediately, whenever this is possible, citing the following reasons:
- If ART is commenced before people have a drop in CD4 number, then they are likely to have a healthy CD4 count in the long term.
- Starting ART immediately possibly reduces the latent reservoir, which could provide patients a better chance of cure if and when this becomes available.
- During PHI patients have extremely high serum viral loads, which possibly increases the risk of onward transmission.
Prof Cohen acknowledged that these points have been disputed by other HIV researchers, and the question of immediate treatment at the time of diagnosis has not yet been settled. Several studies are hoping to address this question over the next few years.