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 are taking HIV medication you should see your provider at least every 3-6 months to check your viral load.

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.

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General Resources

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.

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