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. This document soon became known as the ‘Swiss Statement’ and it 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 unifectious, 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 undetectable 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.
Undetectable = Uninfectious (U=U) is a major worldwide campaign that promotes awareness of this evidence, and its implications for HIV prevention. Find out more from the Prevention Access campaign.