Can't Pass It On

People living with HIV on effective treatment can’t pass it on to a partner.

Research has been building for years, and several large studies have now confirmed it. HIV treatment can suppress the virus to the point that it can’t be transmitted through sex. Learn more about this exciting development in HIV research and help spread the word.


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What does this mean, exactly?

It is now well known that the use of HIV treatment not only improves the health of people living with HIV, but is also a highly effective strategy to prevent HIV transmission. This is because HIV treatment can reduce the amount of virus (viral load) in the blood and other bodily fluids to undetectable levels.

To become and remain undetectable, people living with HIV need to take their HIV treatment as prescribed. In addition to taking HIV medications, regular medical visits are important to monitor viral load to make sure it stays undetectable, and to receive other medical support.

Evidence shows that HIV-positive people who are on treatment, engaged in care, and have an ongoing undetectable viral load:

  • do not transmit HIV to their sexual partners
  • do not transmit HIV to their baby during pregnancy and delivery (if they maintain an undetectable viral load throughout pregnancy and childbirth)
  • have a greatly reduced chance of transmitting HIV through breastfeeding
  • have a greatly reduced chance of transmitting HIV to people they share injection drug use equipment with

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The science

A significant body of research has been accumulating over the years. Between 2016 and 2018, the final findings of four large international studies—PARTNER 1, HPTN 052, Opposites Attract and PARTNER 2—were published. These studies showed that not a single HIV transmission occurred within couples with one HIV-positive partner when the partner living with HIV was on effective treatment.

As a result, we can confidently say that when a person taking antiretroviral treatment achieves viral suppression, they do not transmit HIV to their sex partners.

The Prevention Access Campaign—an international coalition of HIV advocates, activists and researchers who are spreading the word that undetectable HIV is untransmittable—has turned this scientific evidence into a simple message: U=U. Researchers from all the major relevant studies have endorsed it.

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Decisions about treatment should always be made in consultation with a medical practitioner knowledgeable about HIV. Production of this campaign has been made possible through financial contributions from the Public Health Agency of Canada and Gilead Sciences Canada. The views expressed herein do not necessarily represent the views of the funders.

CATIE thanks the British HIV charity Terrence Higgins Trust for granting permission to adapt their “Can’t Pass It On” campaign for a Canadian audience. Visit the original “Can’t Pass It On” campaign web page for more information and resources.