Viral load is the amount of HIV in a person’s blood. A main goal of HIV treatment is to reduce a person’s viral load to an undetectable level. An undetectable viral load means that the level of HIV in the blood is too low to be detected by a viral load test.

Once HIV treatment is started, it usually takes 3 to 6 months for a person’s viral load to reach an undetectable level. Although HIV medicines cannot cure HIV, having an undetectable viral load shows that the medicines are controlling a person’s HIV. Maintaining an undetectable viral load helps people with HIV live longer, healthier lives. In addition, people with HIV who maintain an undetectable viral load have effectively no risk of transmitting HIV to their HIV-negative partners through sex.