Researchers confirmed at the 22nd International AIDS Conference in summer 2018 that the chance of any HIV-positive person with an undetectable viral load transmitting the virus to a sexual partner is scientifically equivalent to zero. The researchers said that ‘zero transmissions mean zero risk’. This announcement in turn means that we can be as confident now that undetectable gay men pose no risk of HIV transmission as we already were for heterosexuals.
The 22nd International AIDS Conference announcement took place on the tenth anniversary of the original ‘Swiss Statement’ in 2008.
The Swiss National AIDS Commission issued a statement for doctors about the impact ARV treatment had in reducing HIV transmission to the sexual partners of their positive patients in 2008 that became known as the ‘Swiss Statement’. The statement declared that an HIV positive person on effective HIV treatment, with an undetectable viral load, cannot transmit HIV through sexual contact.
The Swiss Statement cautioned that, for someone living with HIV to be uninfectious, they had to have good adherence.
- they must take their medication as prescribed
- they must routinely see their HIV doctor
- their viral load must be U=U for at least six months
- they must have no sexually transmitted infections (STIs).
In the decade since the Swiss Statement, a number of important studies have produced evidence to support it:
- In 2011, the HPTN-052 study found that medication dramatically reduced the risk of HIV transmission in sero-different (where one partner is HIV negative and the other is HIV postitive) heterosexual couples.
- In 2016, the PARTNER study reported no HIV transmission among sero-different couples who had condomless sex more than 58,000 times.
- In 2018, the PARTNER 2 study announces that zero transmissions mean zero risk.
Undetectable = Untransmittable (U=U) is a major worldwide campaign that promotes awareness of this evidence, and its implications for HIV prevention. Useful links to find out more about using U=U as an HIV prevention method: