HIV Treatment as Prevention
CDC is working with other federal agencies to ensure that we consistently and accurately describe the prevention effectiveness of HIV treatment and viral suppression for sexual transmission of HIV. This page, and links from this page, contain updated content.
People who are living with HIV should take medicine to treat HIV as soon as possible. HIV medicine is called anti-retroviral therapy, or ART. If taken as directed, HIV medicine reduces the amount of HIV in the body (viral load) to a very low level, which keeps the immune system working and prevents illness. This is called viral suppression—defined as having less than 200 copies of HIV per milliliter of blood. HIV medicine can even make the viral load so low that a test can’t detect it. This is called an undetectable viral load. If you are virally suppressed or have an undetectable viral load, your HIV is under control.
Getting and keeping your HIV under control is the best thing people living with HIV can do to stay healthy. Another benefit of reducing the amount of virus in the body is that it helps prevent transmission to others through sex or needle sharing, and from mother to child during pregnancy, birth, and breastfeeding. This is sometimes referred to as “treatment as prevention.” There is strong evidence about treatment as prevention for some of the ways HIV can be transmitted, whereas more research is needed for other ways.
People living with HIV who take HIV medicine as prescribed and get and keep an undetectable viral load have effectively no risk of transmitting HIV to their HIV-negative sexual partners.
- CDC’s 2017 Gay Men’s HIV/AIDS Awareness Day Dear Colleague Letter discussed viral suppression and sexual transmission.
- CDC’s response to questions regarding the 2017 Gay Men’s HIV/AIDS Awareness Day Dear Colleague Letter.
- CDC’s technical fact sheet Evidence of HIV Treatment and Viral Suppression in Preventing the Sexual Transmission of HIV.
Transmission from Pregnancy, Labor, and Delivery
If a woman living with HIV can take HIV medicine as prescribed throughout pregnancy, labor, and delivery and if HIV medicine is given to her baby for 4-6 weeks after delivery, the risk of transmission from pregnancy, labor, and delivery can be reduced to 1% or less.
Transmission from Sharing Needles or Other Injection Drug Use Equipment
We don’t know whether getting and keeping HIV under control prevents HIV transmission through sharing needles or other injection drug equipment. While we do not yet know if or how much being undetectable or virally suppressed prevents some ways that HIV is transmitted, it is reasonable to assume that it provides some risk reduction.
Transmission from Breastfeeding
We don’t know if a woman living with HIV who has her HIV under control can transmit HIV to her baby through breastfeeding. While we do not yet know if or how much being undetectable or virally suppressed prevents some ways that HIV is transmitted, it is reasonable to assume that it provides some risk reduction.
HIV/AIDS Management Consultation Service for Clinicians
9 a.m. – 8 p.m. ET, Monday – Friday
For more information, visit the National Clinicians Consultation Center.
- Page last reviewed: May 7, 2018
- Page last updated: May 7, 2018
- Content source: Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention