A report that asserts that HIV positive people undergoing effective anti-retroviral treatments carry “no relevant risk of transmission” has been greeted with caution by UNAIDS.

Last week the Swiss Federal Commission for HIV/AIDS announced that “an HIV-infected person on anti-retroviral therapy with completely suppressed viremia (“effective ART”) is not sexually infectious, i.e. cannot propagate HIV through sexual contact.”

The commission said: “residual risk can not be scientifically excluded, but is … negligibly small.”

The statement is based on a person who is compliant with ART, whose the viral load has been suppressed (non-detectable) for at least six months ago and who has no other sexually transmitted diseases.

UNAIDS and World Health Organisation, in a joint release, said that it was still unproven that a suppressed viral load completely eliminated the risk of HIV transmission.

“More research is needed to determine the degree to which the viral load in blood predicts the risk of HIV transmission and to determine the association between the viral load in blood and the viral load in semen and vaginal secretions,” they said.

They continue to recommend a comprehensive package of HIV prevention approaches, including the use of condoms.

“People living with HIV who are following an effective anti-retroviral therapy regimen can achieve undetectable viral loads (the amount of virus in a body fluid such as blood, semen or vaginal secretions) at certain stages of their treatment,” said UNAIDS/WHO.

“Research suggests that when the viral load is undetectable in blood the risk of HIV transmission is significantly reduced.

“However, it has not been proven to completely eliminate the risk of transmitting the virus.

“A comprehensive HIV prevention package includes, but is not limited to, delaying sexual debut, mutual fidelity, reduction of the number of sexual partners, avoidance of penetration, safer sex including correct and consistent male and female condom use, and early and

effective treatment for sexually transmitted infections.”

UNAIDS, whose headquarters are in Switzerland, leads action on AIDS by the UN system and is coordinated in countries through the UN and the joint programmes on AIDS.