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HIV Treatment as Prevention


People with HIV should take medicine to treat HIV as soon as possible. HIV medicine is called antiretroviral therapy, or ART. If taken as prescribed, 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

Getting and keeping an undetectable viral load* is the best thing people 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 syringe 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, but more research is needed for other ways.

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Risk of HIV Transmission With Undetectable Viral Load by Transmission Category


Transmission Category Risk for People Who Keep an Undetectable Viral Load
Sex (oral, anal, or vaginal) Effectively no risk
Pregnancy, labor, and delivery 1% or less
Sharing syringes or other drug injection equipment Unknown, but likely reduced risk
Breastfeeding Substantially reduces, but does not eliminate risk. Current recommendation in the United States is that mothers with HIV should not breastfeed their infants.

The risk of transmitting HIV to the baby can be 1% or less if the mother takes HIV medicine daily as prescribed throughout pregnancy, labor, and delivery and gives HIV medicine to her baby for 4-6 weeks after giving birth.

Resources for Providers

CDC’s technical fact sheet ­­­­­Evidence of HIV Treatment and Viral Suppression in Preventing the Sexual Transmission of HIV

HIV Transmission Prevention: Information for Health Care Providers

Resources for Consumers

Video HIV: Journey to Undetectable | VIH: El Camino Hacia Indetectable

CDC’s consumer info sheet HIV Treatment Can Prevent Sexual Transmission

HIV Basics: Living With HIV

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.

National Clinicians’ Post-Exposure Prophylaxis Hotline (PEPline) 1-888-HIV-4911 (1-888-448-4911) 9 a.m. – 8 p.m. ET, Monday ­­– Friday; 11 a.m. – 8 p.m. ET, weekends and holidays

National Perinatal HIV Consultation and Referral Services (Perinatal Hotline) 1-888-HIV-8765 (1-888-448-8765) 24 hours a day, seven days a week

National Pre-Exposure Prophylaxis Consultation (PrEPline) 1-855-HIV-PREP (1-855-448-7737) 9 a.m. – 8 p.m. ET, Monday ­­– Friday

*The benefits of having an undetectable viral load also apply to people who stay virally suppressed.