The British HIV Association (BHIVA) and the Department of Health’s Expert Advisory Group on AIDS (EAGA) published last month a position statement on the use of HIV treatment by people with HIV to reduce the risk of transmission. For the first time, the document provides health professionals with a consensus statement, developed by UK experts, which can be used to guide discussions with individuals.
Clinicians, epidemiologists, policy experts and HIV-positive people contributed to the document. As this will be a key resource to guide HIV prevention work in England, a substantial part of this bulletin is given over to outlining its key points.
As effective as condoms
The statement notes that there is now conclusive randomised clinical trial evidence, from the HPTN 052 trial, to show that transmission of HIV through vaginal sex is significantly reduced when an HIV-positive person is taking effective antiretroviral therapy (ART). In this trial, early treatment reduced HIV transmission to an uninfected partner by 96%.
“The observed reduction in HIV transmission in a clinical trial setting demonstrates that successful ART use by the person who is HIV positive is as effective as consistent condom use in limiting viral transmission,” it says.
The document includes some explanatory notes, which point out that there has never been a randomised controlled trial of the efficacy of condom use, compared to non-use. For that reason, there are no figures that can be directly compared. However, meta-analyses of observational studies of serodiscordant couples who maintained 100% condom use have found the strategy to be about 80% effective in reducing HIV infection.
The document states that the transmission risk during vaginal intercourse will be “extremely low”, provided certain conditions are fulfilled.
- There are no sexually transmitted infections in either partner. (The document clarifies requirements for STI screening, including following sexual relationships outside a primary partnership.)
- The person with HIV has had a sustained plasma viral load below 50 copies/ml for more than six months, including the most recent test.
- Viral load testing occurs every three to four months (i.e. more regularly than in standard clinical care).
In the document’s explanatory notes, it is explained that in HPTN 052 there was a single confirmed case of HIV transmission from a person on treatment. This individual had only recently begun ART and would not have met the UK position statement’s requirement for an undetectable viral load for at least six months.
The authors say that this justifies the use of the phrase “extremely low risk”. They clarify that this is not the same as “zero risk”. Moreover, with the data that are available, it is not possible to give accurate and meaningful figures for the risk of transmission during a single sexual act.
The published research was primarily done with heterosexual couples and is assumed to relate primarily to vaginal intercourse. Data are not available for anal intercourse, either between men, or between men and women. “However, it is expert opinion that an extremely low risk of transmission can also be anticipated for these practices, provided the same conditions stated above are met,” according to the statement.
Limitations of ART
The position statement notes that no single prevention method can completely prevent HIV transmission. Moreover, antiretroviral treatment has no effect on other sexually transmitted infections, whereas condoms can prevent their spread.
Discussion with people with HIV
Healthcare professionals should discuss the impact of ART on sexual transmission with all people living with HIV. For people not currently on therapy, the possibility of starting treatment in order to reduce transmission risk should be discussed. (BHIVA treatment guidelines already make a similar recommendation).
It is important that these discussions cover the ‘necessary conditions’ for ART to reduce transmission risk - long-term adherence, frequent STI screening and regular viral load measurements.