Undetectable = Untransmissible
What is U=U?
Medicines to treat HIV can eliminate the risk of sexual transmission. People with HIV who take their medication every day and maintain an undetectable viral load (<200copies/ml) are effectively at zero risk of transmitting HIV to their partner. This is known as undetectable = untransmittable or U=U (#UequalsUSF).
If you or your partner stops HIV medications for several days you may be at risk. Consider PrEP and/or condoms to prevent HIV and contact your provider.
Summary of Latest Research
Science supports and validates the message of U=U. Data from studies provide the evidence.
- There were zero HIV sexual transmissions among couples if the HIV-positive partner was undetectable after >150,000 sex acts
- No HIV transmissions occurred in studies even when people got STIs
However, we don’t have enough data to know if being undetectable prevents HIV transmission among people who inject drugs.
San Francisco Resources
Spinelli, Matthew and Monica Gandhi. “Undetectable Equals Untransmittable.” The Clinical Edge, UCSF Center for HIV Information, 16 Jan. 2018, hivinsite.ucsf.edu/InSite?page=md-expert-spinelli
Studies & Conference Abstracts
Rodger, Alison J., et al. “Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy.” Jama 316.2 (2016): 171-181.
Bavinton, Benjamin R., et al. “Viral suppression and HIV transmission in serodiscordant male couples: an international, prospective, observational, cohort study.” The Lancet HIV 5.8 (2018): e438-e447.
Rodger A et al. Risk of HIV transmission through condomless sex in gay couples with suppressive ART: the PARTNER2 study expanded results in gay men. 22nd International AIDS Conference, Amsterdam, abstract WEAX0104LB, 2018.