The amount of HIV in your body fluids is called your viral load. Effective HIV treatment (antiretroviral therapy) suppresses the amount of HIV in your body fluids to the point where standard tests are unable to detect any HIV, or can only find a tiny trace. Doctors call this ‘virological suppression’ but it is often known as ‘having an undetectable viral load’ or ‘being undetectable’.
Having an undetectable viral load does not mean you are cured of HIV. If you stopped taking treatment, your viral load would increase and once again be detectable. Having an undetectable viral load does mean that there is not enough HIV in your body fluids to pass HIV on during sex. In other words, you are not infectious. For as long as your viral load stays undetectable, your chance of passing on HIV to a sexual partner is zero. As the campaign slogan puts it, 'Undetectable equals Untransmittable' or 'U=U'.
Find out more in this factsheet.