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HIV: Undetectable Equals Untransmittable (U=U)

People living with HIV can lead long and healthy lives by taking medicines that keep the virus undetectable. People who maintain an undetectable viral load for at least six months cannot transmit HIV though sex. This is known as “undetectable equals untransmittable,” or “U=U.”


HIV treatment is safer and more effective than ever. Antiretroviral medicines do not cure HIV infection or remove the virus from the body, but, when taken as prescribed, they can stop the virus from multiplying.

The sooner a person living with HIV starts treatment, the less damage the virus can do to their body. Medicine can reduce the virus in the body to such a low level that it does not show up on tests and cannot be passed through sex. This is known as an undetectable viral load.

If you are living with HIV, be sure to take your medicines as prescribed and see an HIV doctor for regular checkups. You can contact the Positive Life Workshop, The Undetectables program or the NYC Ryan White Care Coordination program to start HIV treatment and stay in care. You can also find a provider near you on the NYC Health Map, or by texting “CARE” to 55676.

In New York City, HIV testing and treatment services are available regardless of your ability to pay or your immigration status.

HIV and Your Sexual Health

If you do not know your HIV status, get tested. HIV tests are fast and easy, and they are also free at NYC Sexual Health Clinics. A positive test is an opportunity to treat HIV, stay healthy and prevent HIV transmission. A negative test gives you the chance to discuss ways to stay negative, such as using condoms or taking daily pre-exposure prophylaxis (PrEP).

If you do not have HIV, PrEP can help you avoid it. PrEP is a safe and effective daily pill that prevents HIV.

If you have HIV that is undetectable, you cannot pass it through sex, even if you do not use condoms. Condoms can still help protect against other sexually transmitted infections (STIs) and unplanned pregnancy.

Scientific Evidence

Several recent scientific studies looked at thousands of couples undergoing HIV treatment. Among the participants in the studies who had undetectable HIV, none passed the virus to their sex partner.

Learn more about the methodology and results of these studies:

Additional Resources

More information