Learn more about HIV :: HIV Transmission

HIV Transmission

HIV must be present - Infection may only occur if one of the persons involved in an exposure situation is infected with HIV. Some people assume that certain behaviors or exposure situations can cause HIV disease, even if the virus is not present. This is not true.

There needs to be enough virus present - The concentration of HIV determines whether infection will occur. In blood, for example, the virus is very concentrated. A small amount of blood is enough to infect someone. Also, the concentration of virus in blood or other fluids can change, in the same person, over time.

Infectious Fluids - HIV can be transmitted from an infected person to another through:

• Blood
• Semen (including pre-seminal fluid)
• Vaginal secretions
• Breast milk

Non-Infectious Fluids

• Saliva is NOT considered to be infectious. The only time saliva would pose a risk would be if it had blood present in it. There are no documented cases of HIV transmission through saliva. A protein in the mouth attaches itself to the surface of blood cells and blocks infection by HIV appears to be present in the mucous membrane in the mouth at a level sufficient to reduce the concentration of HIV in saliva to non-infectious levels.
• Urine and Tears are NOT considered infectious. While HIV has been found in urine and tears, it is not concentrated in an amount sufficient for transmission.
• Sweat, Feces, Vomit are NOT considered infectious. HIV has never been found in these materials. The only possible risk would be if blood were present.

HIV must get into the bloodstream - It is not enough to be in contact with an infected fluid for HIV to be transmitted. Healthy, intact skin does not allow HIV to get into the body.

HIV can enter through an open cut or sore, or it can find entry into the bloodstream through the veins or through contact with the mucous membranes. Transmission risk is very high when HIV comes in contact with veins during needle sharing. Transmission risk is also high when HIV comes in contact with the more porous mucous membranes in the genitals (the head of the penis, the vulva/vagina) and the anus/rectum during penis/vagina, penis/anus intercourse. Transmission is also possible when HIV comes in contact with the mucous membranes of the mouth through performing oral sex.

Sexual Transmission

HIV can be transmitted through sexual intercourse, both vaginal and anal. HIV can easily pass through the mucous membranes in the genitals and the rectum, so the receptive partner is at increased risk during anal intercourse and somewhat increased risk during vaginal intercourse.

HIV can also be transmitted through oral sex. Conditions such as bleeding gums and poor oral health increase the risk of transmission and through oral sex.

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Non-sexual Transmission

HIV can be transmitted by contact between infectious fluids and bleeding cuts or open sores in the skin. However, healthy, intact skin does not allow HIV to enter the body, and provides an excellent barrier against the virus.

Sharing Needles Sharing syringes to inject medicines, hormones, steroids or illegal drugs can pass blood directly from one person's blood stream to another's. It is also a very efficient way to transmit HIV and other blood borne viruses such as Hepatitis B (HBV) and Hepatitis C (HCV).

Tattoos and Piercing There have been NO documented cases of transmission of HIV by piercing or tattooing. However, there are documented cases of Hepatitis B (HBV) transmission through these routes. Since Hepatitis B and HIV are transmitted by the same activities, there may be a possibility of HIV transmission through tattoos and piercing.

Blood Transfusions Since March 1985, all blood in the United States has been screened for HIV using the HIV antibody test. This practice has almost eliminated the risk of getting HIV through a blood transfusion in the United States.

Hemophiliacs Since March 1985, all blood in the United States has been screened for HIV with the HIV antibody test. This practice has almost eliminated the risk of getting HIV through a blood transfusion in the United States. Other blood products have transmitted HIV, but current blood screening should prevent infection from these products.

Donor Insemination This is not a regulated industry. It is recommended that donor semen be checked for the presence of HIV. When collecting semen, donors should be tested for HIV antibodies when the sample is taken. The semen should then be frozen. The donor should then be retested three months later to avoid the risk of a "window period" effect. The semen should not be used before the procedure is completed.

Organ Donation People who are infected with HIV are encouraged not to donate organs or tissue for transplant purposes. There were very few cases of organ or tissue transplant HIV transmission from 1985 until 1994 when new government guidelines were implemented to reduce the risk of transplant transmission. These guidelines require blood from donors be tested for various strains of HIV. Also, the donor medical history must show no evidence of risk factors or clinical symptoms of HIV infection.

Mother to Infant Transmission— It is possible for a mother who has HIV to pass the virus to her fetus by exposure to blood and vaginal fluids during birth, or through breast milk breast during feeding. HIV infected pregnant women pass HIV on to their newborn 25%-30% of the time without medical intervention and 8% of the time when medicines are given during pregnancy and birth.

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