COLUMN: Treatment as prevention – where the evidence is at
Commencing HIV treatment can significantly improve the long-term health of someone living with HIV. Studies have confirmed that HIV treatment has benefits that go beyond improving individual health. These studies demonstrate that HIV treatment reduces the levels of HIV in blood, semen and rectal fluid to undetectable levels. The notion that HIV treatment can prevent HIV transmission and assist in reducing HIV transmissions is known as 鈥榯reatment as prevention鈥�.
Treatment as prevention is part of a suite of HIV prevention measures that include community level testing, condom reinforcement messages, post-exposure prophylaxis and regular HIV/STI testing.聽 These measures provide the community with a powerful and exciting opportunity to significantly reduce the rate of HIV transmission in our community.
While treatment as prevention is an exciting prospect, it is important to understand the challenges that it presents to gay men. First, the research underpinning treatment as prevention involved couples who practise vaginal sex.聽 Secondly, there is no definitive proof that being on treatment and having an undetectable viral load means no risk of transmission. To better understand HIV treatment as prevention, in general and within the context of gay men, further research has been initiated.
The Strategic Timing of AntiRetroviral Treatment (START) study is looking at the benefits of commencing treatment early versus deferring treatment. It is hoped that this study will provide increased knowledge on the effect of early treatment on the health of HIV positive people.
A New York study (HPTN 065) will assess the feasibility of HIV treatment as prevention as an individual treatment strategy in the US. This study will consider the effectiveness of community based testing, linkage to medical care, and for those who need it, treatment; as a singular prevention strategy.
Here in Australia, the Opposites Attract study, which involves sero-discordant couples (poz/neg couples), is conducting a semen sub study. This sub study will measure the risk of HIV transmission through seminal fluid. Research suggests that the levels of the HIV virus in blood are not always the same as the levels of the HIV virus in semen. The Opposites Attract study will provide important data on the extent to which treatment impacts upon the levels of the HIV virus in semen.
Treatment as prevention is another option for people who are at risk of exposure to HIV.聽 The current evidence suggests that HIV treatment should complement, rather than substitute, existing HIV prevention strategies.
The results of the medical trials referred to above will expand our understanding of treatment as prevention. This knowledge will inform HIV prevention programs, and support individuals who are trying to determine whether to commence treatment, and if so, when.
VAC/GMHC
Heath Paynter
