During a press conference, researchers announced that low viral load prevents transmission between sexual partners in both anal and vaginal sex.

Statistical analysis shows that the maximum likely chance of transmission via anal sex from someone on successful HIV treatment was 1% a year for any anal sex and 4% for anal sex with ejaculation where the HIV-negative partner was receptive; but the true likelihood is probably much nearer to zero than this.

When asked what the study tells us about the chance of someone with an undetectable viral load transmitting HIV, presenter Alison Rodger said: "Our best estimate is it's zero."