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 prevents 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.

graphic of a bottle of pills

A person with HIV who takes HIV medicine as prescribed and gets and stays virally suppressed or undetectable can stay healthy and will not transmit HIV to their sex partners.

Risk of HIV Transmission With Undetectable Viral Load by Transmission Category

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) Studies have shown no risk of transmission
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.

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

Resources for Providers

Learn more about talking to patients with HIV about treatment as prevention and the benefits of vial suppression.

Perinatal HIV Hotline

Provides clinicians with around-the-clock advice on indications and interpretations of HIV testing in pregnancy, and consultation on antiretroviral use during pregnancy, labor and delivery, and the postpartum period.
1-888-448-8765 | 24 hours, seven days a week


Provides expert guidance in managing health care worker exposures to HIV and hepatitis B and C. Clinicians receive immediate post-exposure prophylaxis (PEP) recommendations.
1-888-448-4911 | Occupational PEP: 11 am to 8 pm EST, seven days a week | Non-occupational PEP: 9 am to 8 pm EST, Monday through Friday; 11 am to 8 pm EST, weekends and holidays


Provides expert guidance on considerations for providing pre-exposure prophylaxis (PrEP) to people who don’t have HIV as part of an HIV prevention program.
1-855-448-7737 | 9 am to 8 pm EST, Monday through Friday

Resources for Consumers

If you have HIV, it’s important to make choices that keep you healthy and protect others. Learn more about living with HIV.

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