U=U stands for Undetectable = Untransmittable. U=U is a health promotion campaign used to promote the scientific consensus that HIV cannot be sexually transmitted when a person living with HIV is on treatment and maintains a viral load (i.e., the amount of virus in the blood) of less than 200 copies/ml (measured every 4-6 months). Health professionals can increase the uptake of treatment, prevent new infections, and reduce HIV-related stigma by fully understanding and communicating the undeniable benefits of HIV treatment to people living with HIV and their sexual partners.
OuvrirSource : Public Health Agency of Canada