UNAIDS: U=U ExplainerFact sheets Global
“Undetectable = Untransmittable is the message of a new UNAIDS Explainer. With 20 years of evidence demonstrating that HIV treatment is highly effective in reducing the transmission of HIV, the evidence is now clear that people living with HIV with an undetectable viral load cannot transmit HIV sexually.
Three large studies of sexual HIV transmission among thousands of couples, one partner of which was living with HIV and the other was not, were undertaken between 2007 and 2016. In those studies, there was not a single case of sexual transmission of HIV from a virally suppressed person living with HIV to their HIV-negative partner. The Explainer cautions, however, that a person can only know whether he or she is virally suppressed by taking a viral load test.”