U=U
Undetectable equals Untransmittable: a man with HIV on treatment whose viral load is undetectable cannot pass HIV on through sex.
U=U means Undetectable equals Untransmittable: a man living with HIV who takes his treatment and keeps his viral load undetectable cannot pass HIV on through sex. On dating profiles it is the short answer to the question every positive guy used to dread, and it has done more to fight HIV stigma than any poster campaign before it.
Undetectable means the amount of virus in the blood is so low that standard tests can't find it; in the big studies the threshold was under 200 copies per milliliter. It is not a cure: the virus is still in the body, held down by daily treatment. And it says nothing about other STIs.
The science
The proof came from couples. The PARTNER studies followed gay and straight couples in Europe in which one partner was HIV-positive on treatment and the other negative, while they had sex without condoms. The second phase, PARTNER2, published in The Lancet in 2019, followed 782 gay couples for more than 1,500 couple-years and found zero transmissions from a partner with a suppressed viral load. The lead author put it simply: the risk is effectively zero.
The slogan
Doctors had known it for years, but few said it out loud. The slogan came from activism: Prevention Access Campaign, founded by Bruce Richman, a gay man living with HIV, launched U=U in 2016 and pushed health departments and HIV organizations to sign a consensus statement backing it; New York City's health department was the first public health body to sign. The formula spread to clinics, health agencies and, inevitably, the apps.
On the apps
Most apps now let you list your HIV status, and "poz undetectable" or "U=U" sits next to "neg, on PrEP" as one of the normal answers. Together the two changed gay sex in a decade: a bareback hookup between a negative man on PrEP and a positive man who is undetectable carries no HIV risk at all, which is why words like raw lost much of their old charge. A man who rejects someone just for being poz and undetectable is now more likely to be called out than praised for caution.
U=U holds for a man who takes his treatment every day and has his viral load checked regularly; a doctor confirms when it is undetectable. Condoms, PrEP and testing are still the tools against syphilis, gonorrhea and the rest.
Related terms
Sources 2
- Rodger, Alison J., et al. "Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study." The Lancet 393, no. 10189 (2019): 2428-2438. https://doi.org/10.1016/S0140-6736(19)30418-0
- "Bruce Richman: The Reluctant Activist Who Practically Made Undetectable = Untransmittable a Household Term." The Advocate, 17 January 2018. https://advocate.com/hiv-stops-me/2018/1/17/bruce-richman-reluctant-activist-who-practically-made-undetectable-untransmittable-household-term