Prevention benefits of ART
A 2011 trial has confirmed that if an HIV-positive person adheres to an effective ART regimen, the risk of transmitting the virus to their uninfected sexual partner can be reduced by 96%. A recent study published in 2019 showed that the risk of HIV transmission through sex, where condoms are not used, in serodifferent gay couples is effectively zero when HIV viral load is suppressed through ART treatment. The WHO recommendation to initiate ART in all people living with HIV will contribute significantly to reducing HIV transmission.

Pre-exposure prophylaxis (PrEP) for HIV-negative partner
Oral PrEP of HIV is the daily use of ARV drugs by HIV-negative people to block the acquisition of HIV. More than 10 randomized controlled studies have demonstrated the effectiveness of PrEP in reducing HIV transmission among a range of populations including serodiscordant heterosexual couples (where one partner is infected and the other is not), men who have sex with men, transgender women, high-risk heterosexual couples, and people who inject drugs.

WHO recommends PrEP as a prevention choice for people at substantial risk of HIV infection as part of a combination of prevention approaches. WHO has also expanded these recommendations to HIV-negative women who are pregnant or breastfeeding.

Post-exposure prophylaxis for HIV (PEP)
Post-exposure prophylaxis (PEP) is the use of ARV drugs within 72 hours of exposure to HIV to prevent infection. PEP includes counselling, first aid care, HIV testing, and administration of a 28-day course of ARV drugs with follow-up care. WHO recommends PEP use for both occupational and non-occupational exposures and for adults and children.