HIV positive men on antiretroviral drugs can’t transmit virus, study shows

Gay couple kissing on sofa

A new study has indicated that there is zero risk of transmitting HIV to a partner while on effective antiretroviral treatment.

The study—which is published in The Lancet and is called PARTNER2—investigated almost 1,000 gay male couples who did not use condoms across Europe over more than eight years where one partner had the virus.

Over the course of eight years, just 15 of the HIV-negative men involved contracted the virus—however, researchers were able to confirm through genetic testing that none of those men contracted the virus from their partner.

HIV study indicates that effective antiretroviral therapy prevents transmission of virus

The study is the largest of its kind, and researchers say it provides conclusive evidence that having an undetectable viral load while on antiretroviral therapy (ART) means that the virus is untransmittable.

The study found that the effective use of ART for HIV-positive men involved in the study prevented around 472 transmissions of the virus.

“Our findings support the message of the international U=U campaign, that an undetectable viral load makes HIV untransmittable.”

– Alison Rodger, UCL, who co-led the research

The findings support the international U=U (undetectable equals untransmittable) campaign, which has argued that effective ART means people with the virus can have sex without the fear of transmitting it to partners.

This is the second phase of the study. The first, which was called the PARTNER study, took place between September 2010 and May 2014, with results published in 2016. That phase of the study surveyed both heterosexual couples and gay male couples.

Man looking out window representing effects of men living with HIV

The study investigated almost 1,000 gay male couples who did not use condoms, with one of the partners having HIV. (Pexels)

For this phase of the study, researchers only recruited gay male couples. The men involved in the study had frequent follow-ups where they completed questionnaires on their sexual behaviour. HIV-negative partners were regularly tested for the virus and HIV-positive partners were regularly tested to ensure that they were undetectable.

37 percent of men without the virus reported having had anal sex without a condom with other partners outside of their relationship. Just 5 percent of men with the virus reported missing ART for four days or more.

Study offers “conclusive evidence” of antiretroviral therapy’s efficacy

The researchers noted that the study was limited by the fact that most participants who did not have the virus were white with an average age of 38. Most new cases occur in gay men under the age of 25.

Dr Michael Brady, Medical Director at Terrence Higgins Trust and National NHS Adviser for LGBT Health said it was “impossible to overstate the importance of the findings.”

“The PARTNER study has given us the confidence to say, without doubt, that people living with HIV who are on effective treatment cannot pass the virus on to their sexual partners. This has incredible impact on the lives of people living with HIV and is a powerful message to address HIV-related stigma.”

Professor Alison Rodger from UCL, who co-led the research, said the findings provide “conclusive evidence for gay men that the risk of HIV transmission with suppressive ART is zero.”

“Our findings support the message of the international U=U campaign, that an undetectable viral load makes HIV untransmittable. This powerful message can help end the HIV pandemic by preventing HIV transmission, and tackling the stigma and discrimination that many people with HIV face.

“Increased efforts must now focus on wider dissemination of this powerful message and ensuring that all HIV-positive people have access to testing, effective treatment, adherence support and linkage to care to help maintain an undetectable viral load.”