HIV treatment as a highly effective HIV prevention method

Overview

In addition to its important health benefits, HIV treatment helps to reduce or eliminate the risk of passing HIV to others. HIV treatment works by controlling the replication of HIV in the body — that is, it reduces HIV’s ability to make copies of itself. When HIV replication is controlled, the amount of virus (also known as the viral load) in the blood and other bodily fluids decreases. When a person’s viral load becomes so low that standard blood tests aren’t able to detect the virus, this is known as an undetectable viral load.

When a person has an undetectable viral load, they cannot pass HIV through sex. We know this because of a large amount of evidence that shows no HIV transmissions between sex partners when the partner with HIV has an undetectable viral load. This is true when no other prevention method is used (e.g., condoms or PrEP) and regardless of whether one of the partners has a sexually transmitted infection (STI).

We also know that when a person has an undetectable viral load before becoming pregnant, and maintains it during labour and delivery, their baby will not be born with HIV. Research suggests that having an undetectable viral load significantly lowers the risk of transmitting HIV through breastfeeding, but that there is still a very low chance of transmission. Therefore, in Canada it is recommended that people with HIV feed their babies formula rather than breastfeeding. However, it is also recommended that people who choose to breastfeed should be supported by their medical team to do so as safely as possible.

Evidence suggests that the risk of HIV transmission when sharing equipment to inject drugs is lowered when a person has an undetectable viral load. However, there is not a lot of research on this, so we don’t know how much the risk is reduced. The best way to prevent transmission of HIV and other infections such as hepatitis B and C is to use new needles and other injecting equipment (e.g., cookers and filters) for every injection.

To learn more about the prevention benefits of HIV treatment, check out:

HIV treatment and an undetectable viral load to prevent HIV transmission – This fact sheet outlines the prevention benefits of HIV treatment, through sex, drug use, pregnancy and breastfeeding.

CATIE statement on the use of antiretroviral treatment (ART) to maintain an undetectable viral load as a highly effective strategy to prevent perinatal transmission of HIV – This CATIE statement provides recommendations for supporting people with HIV who are considering having a baby, are pregnant or who have recently had a baby. It includes research about how HIV treatment can prevent perinatal transmission.

Other helpful resources:

The Power of Undetectable: What you need to know abut HIV treatment as prevention – This client resource explains the prevention benefits of HIV treatment in plain language.

HIV Treatment to Prevent HIV – This video for clients and service providers explains how HIV treatment works to prevent transmission and provides key messages about this prevention strategy.

Growing Your Family: An Introduction to Pregnancy Planning, Surrogacy and Adoption for People Living with HIV – This resource provides an introduction to the options available for people with HIV who want to have children, including pregnancy, surrogacy and adoption. It explains how to prevent passing HIV to a baby for those who plan to be the biological parent of a child.