A landmark study has shown that the risk of passing HIV is nonexistent when the virus is suppressed by effective anti-retroviral treatment (ART), signalling that an end to the disease that has killed 35 million people worldwide is nearer.

Nearly 1000 male couples of mixed-HIV status from 14 countries in Europe participated in the study, which lasted eight years.

With each couple, one partner was HIV-negative, while the other was positive, but undergoing a successful ART regime.

During the course of the study, which was called PARTNER2, the couples had unprotected sex, but because of the virus-suppressant treatment, there were no cases of transmission.

Fifteen men did become infected during the course of the study, but further testing determined that their infection had been the result of sexual relationships with someone other than their partner.

Alison Rodger, a professor at University College London who co-led the research, told CNN that if people can get the right treatment, the the virus can be eradicated.

"We've got a way to go to get people easier access to testing and treatment, but if we could get global coverage, then we could really make headway in eliminating the virus," she said.

A similar study, PARTNER1 focused on heterosexual couples.

The results, which were published in 2016, also showed no risk of transmission.

"It's brilliant - fantastic. This very much puts this issue to bed," Rodger said, according to The Guardian.

She added that the results 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 (Undetectable=Untransmittable) campaign that an undetectable viral load makes HIV untransmittable."

According to the study's authors, "the results from the PARTNER studies support wider dissemination of the message of the U=U campaign that risk of transmission of HIV in the context of virally suppressive ART is zero.

"This dissemination is necessary to promote the benefits of early testing and treatment and to tackle stigma, discrimination, and criminalisation laws that continue to affect HIV-positive people."

The study was led by the University College London and the University of Copenhagen and funded by the National Institute for Health Research, Europe's largest national clinical research funder.