Three reasons why CATIE supports U=U for sexual transmission


CATIE recently endorsed the Consensus Statement of the Prevention Access Campaign, celebrating the fact that “undetectable equals untransmittable.” This revolutionary statement, pushed forward by a dedicated group of people living with HIV, has prompted CATIE to reflect on our sexual HIV prevention messaging.

The research on treatment as prevention has been slowly accumulating for many years. As an evidence-based organization, CATIE now recognizes that the evidence on undetectable viral load has reached a point where we are compelled to take our messaging a step further. We can comfortably say that when a person taking antiretroviral treatment has an ongoing undetectable viral load and is engaged in care, they do not transmit HIV to their sexual partners.

This is why we decided to sign on to U=U:

1. The science supports it (and the scientists do too)!

We have learned so much about the benefits of starting HIV treatment early. We now know that people who start treatment as soon as possible after becoming HIV-positive can live long, healthy lives, and are less likely to develop HIV-related conditions or other serious health issues.

We also know that taking treatment to maintain an undetectable viral load has significant prevention benefits. In July 2016, two large studies (PARTNER and HPTN 052) published final results showing that not a single HIV transmission occurred between serodiscordant sexual partners when the person living with HIV was on treatment and had an undetectable viral load.

The Prevention Access Campaign was quick to turn this new evidence into a simple and meaningful message (U=U). Researchers from all the major studies endorsed this message. As Dr. Myron Cohen (the principal investigator of HPTN 052) stated: “we now have 10,000 person years (of follow-up) with zero transmissions from people who are suppressed.” So why have others, CATIE included, been slower to accept this game-changing language?

The idea of “zero risk” is uncomfortable to many because it is impossible for research to ever conclude that a risk is zero. Statistically, we cannot rule out that a very small risk may exist, no matter what the data show us. However, focusing on the possibility of a very rare event can also be misleading. In this case, a large body of evidence is telling us that people with undetectable viral loads do not transmit HIV, and in research jargon we say that the risk is negligible (meaning insignificant or not worth considering).

But what does negligible mean to the average person? It certainly does not convey the excitement that people living with HIV are feeling about this amazing news. Negligible may be an accurate word but it is not a suitable message. If the risk is negligible then we must be willing to accept that it is not important.

2. People living with HIV need to hear this message

It is important for people living with HIV to hear this message so they can be confident in their ability to have healthy sex lives. People living with HIV continue to face stigma that affects their lives in many ways. By continuing to focus on a risk that is negligible, we do nothing to combat HIV-related stigma. The U=U message can reduce HIV stigma by removing the fear that people living with HIV are “infectious” and “risky” sex partners.

3. U=U is a smart HIV prevention message

HIV-negative people need to know that an HIV-positive person who is on treatment and engaged in care, and maintains an undetectable viral load, is a very safe sexual partner because their HIV is diagnosed and the virus is controlled. This is counter to what prevention messaging said for years, where the HIV-negative partners of people living with HIV were considered to be at highest risk. We now know that the majority of HIV transmissions come from people who are living with HIV and don’t know it (the undiagnosed). This paradigm shift requires us to take up new messages that clearly communicate where the risk actually lies – not with HIV-diagnosed people who have and maintain undetectable viral loads.

We need to ensure that our HIV prevention messages help, rather than harm, the people to whom we are speaking. With a little creativity and boldness, these messages can be meaningful to the communities we serve while remaining strongly grounded in the science.


Camille Arkell is CATIE’s Knowledge Specialist, Biomedical Science of Prevention. She has a Master’s of Public Health degree in Health Promotion from the University of Toronto, and has been working in HIV education and research since 2010.



7 Responses

  1. Thank you so much for this detailed explanation, Ms. Arkell. This is exactly what many people living with HIV need to hear. I have been undetectable since 1996 and never knew until this past summer that I could not transmit the virus; I have been shunned, I compensated by giving up any possibility of finding someone to love, and I am not alone.
    I understood that it would take CATIE a while to approve U=U, achieve consensus with its Board of Directors, and get staff to buy into this kind of messaging. I believe that largely due to CATIE’s leadership, the GMSH came out today with outstanding plain English messaging for gay men.
    Thank you from all of us at the Prevention Access Campaign. Denis LeBlanc, Ottawa, Global liaison for PAC.

  2. Love this- and helping people understand however I am wondering one thing (not to science or content) but the fact that Untransmittable is NOT a word! It is simply not a word. Non-transmittable or non-infectious… these are real words. Why are using messaging with non words?
    The information is 100% awesome- needs to be shouted from rooftops… just confused about the choice (besides alliteration) for making up a word?

    • I received a response from Prevention Access with great explanation… all good folks- feel free to remove (although it is still waiting) from site 🙂

        • It was a bit of a long chain going through discussions with people working in English language studies- I will give a synopsis 🙂 It helped me understand much better and will certainly help me communicate the message without feeling so odd about the word- I think it really comes to the campaign which needs to be well received… and our scientific words…we all know, are not that user friendly 😉 So this helped me understand much better, I also appreciated the rigor they went through to determine the use of the word!

          Prevention Access: “We initially used “uninfectious”, which is a common word in research, but folks from the US HIV positive community felt it was stigmatizing because the alternative meant someone was “infectious”.

          Comment: Un- is a very versatile and productive prefix, so I see no good reason it can’t be used with transmittable. Because it is so widely used, dictionaries don’t always give every instance in which un- can be added to a word (just as they don’t include every regular past tense form of a verb or plural of a noun).
          Comment: Presence in a dictionary isn’t a great test though. Language is always in flux and dictionaries are out of date before they’re published!
          Comment : I’m glad to see the campaign. Since transmission is used so often in reference to HIV, I think it justifies the use of untransmittable in the campaign. I hope others agree. If I think of anything more that’s relevant I’ll let you know.

  3. I attended the forum last night in Toronto at (ACT), very informative
    discussion and some good feedback from the community group I’mean proud that the AIDS Committee of Toronto is working to get the clear message out about U Equals U along with Catie and many other countries.

    1. Is this being forwarded to all the AIDS Service Organizations in Ontario?

    2. I feel ACT should hold a forum for the Doctor’s and Healthcare providers about U Equals U!

    3. Catie should be sending out the literature about U Equals U
    Undetectable = Untransmittable to all ASO’s in Canada!

    Thank You, for informing our community at large about the misinterpretation about U = U Undetectable = Untansmittable.

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