Fluids of Transmission

Which Body Fluids Can Transmit HIV?

HIV transmission can occur when fluids containing HIV from an infected person enter the body of an uninfected person. These fluids include:

• Blood
• Semen (cum)
• Pre-seminal fluid (pre-cum)
• Vaginal fluid
• Breast milk

HIV can enter the body through:

• Lining of the anus or rectum
• Lining of the vagina and/or cervix
• Opening to the penis
• Mouth that has sores or bleeding gums
• Cuts and sores
• Needles (syringes)

Healthy skin is an excellent barrier against HIV and other viruses and bacteria. HIV cannot enter the body through unbroken skin.

These are the most common ways that HIV is transmitted from one person to another:

• Having sex (anal, vaginal, or oral) with someone who is HIV-positive
• Sharing needles or injection equipment ("works") with a user who is HIV-positive
• From HIV-positive women to their babies—before or during birth, or through breastfeeding after birth

Some healthcare workers have been infected after being stuck with needles contaminated with HIV-infected blood—or, less frequently, by having infected blood splashed into their eyes, nose, mouth, or into an open cut or sore.

For more information, see CDC's HIV Transmission and Exposure to Blood: What Healthcare Personnel Need to Know (PDF).

HIV also can be transmitted through transfusion of infected blood or blood clotting factors. However, since 1985, all donated blood in the United States has been tested for HIV. The risk of infection through transfusion of blood or blood products is extremely low—but if you have risk factors for HIV, you should avoid donating blood. It is important to remember that you should not donate blood for the purpose of getting tested for HIV.

For more information, see CDC’s How safe is the blood supply in the United States?