This post is by Global Center Director Christine Lubinski, reporting this week from CROI in San Francisco.
The notion of treatment as prevention got a significant boost this week at CROI, where the results of a new study were presented by Deborah Donnell, MD, of the Fred Hutchinson Cancer Research Centre in Seattle. Dr. Donnell detailed exciting evidence that ART can prevent HIV acquisition, at least in the context of heterosexual, HIV discordant couples.
In a multinational prospective study, researchers followed of a large cohort of couples in south and east Africa and looked at the role of ART in reducing transmission risks. The study tested the uninfected partner at the beginning of the study and at 3 month intervals, while providing free condoms and intensive prevention counseling to the couples. The infected partners were placed on ART when their CD4 counts dropped below 250. Thirty-one percent of the infected female partners and 28 percent of the infected male partners reported unprotected sex.
The study was able to confirm whether HIV transmission occurred within the partnership through special testing. There were 151 HIV transmission events, 108 of which were linked to partnerships. Only one transmission event was found within a partnership where the infected person was on ART, while 102 HIV infections occurred within partnerships with no ART. There was a 92 percent reduced risk of infection for the discordant partnerships where the partner was on ART.
HIV transmission occurred at all CDR levels, but transmission rates were highest when the infected partners CD4 count was under 200. This finding emphasizes the prevention imperative to expand ART access to the 40-some percent of persons in developing countries with CD4 counts below 200 who do not yet have access.
Interestingly, there was a significant reduction in unprotected sex in the partnerships where ART was introduced, from 6.2 percent to 3.7 percent.
Dr. Donnell noted that further research and more data is needed to evaluate whether prevention benefits would persist during long-term ART use. Click here to read a Reuters story on the study.