How Is HIV Transmitted?
A person who is HIV-infected carries the virus in certain body fluids, including blood, semen, vaginal secretions, and breast milk. The virus can be transmitted only if such HIV-infected fluids enter the bloodstream of another person. This kind of direct entry can occur (1) through the linings of the vagina, rectum, mouth, and the opening at the tip of the penis; (2) through intravenous injection with a syringe; or (3) through a break in the skin, such as a cut or sore. Usually, HIV is transmitted through:
* Unprotected sexual intercourse (either vaginal or anal) with someone who is HIV-infected.
Women are at greater risk of HIV infection through vaginal sex than men, although the virus can also be transmitted from women to men. Anal sex (whether male-male or male-female) poses a high risk mainly to the receptive partner, because the lining of the anus and rectum are extremely thin and filled with small blood vessels that can be easily injured during intercourse.
* Unprotected oral sex with someone who is HIV-infected.
There are far fewer cases of HIV transmission attributed to oral sex than to either vaginal or anal intercourse, but oral-genital contact poses a clear risk of HIV-infection, particularly when ejaculation occurs in the mouth. This risk is increased when either partner has cuts or sores, such as those caused by sexually transmitted diseases (STDs), recent tooth-brushing, or canker sores, which can allow the virus to enter the bloodstream.
* Sharing needles or syringes with someone who is HIV-infected.
Laboratory studies show that infectious HIV can survive in used needles for a month or more, and should never reuse or share syringes, water, or drug preparation equipment. This includes needles or syringes used to inject illegal drugs such as heroin, as well as steroids. Other types of needles, such as those used for body piercing and tattoos, can also carry HIV.
* Infection during pregnancy, childbirth, or breast-feeding (mother-to-infant transmission).
Any woman who is pregnant or considering becoming pregnant and thinks she may have been exposed to HIV even if the exposure occurred years ago should seek testing and counseling. Mother-to-infant transmission has been reduced to just a few cases each year in the U.S., where pregnant women are tested for HIV, and those who test positive are provided with drugs to prevent transmission and counseled not to breast-feed.
How Is HIV Not Transmitted?
HIV is not an easy virus to pass from one person to another. It is not transmitted through food or air (for instance, by coughing or sneezing). There has never been a case where a person was infected by a household member, relative, co-worker, or friend through casual or everyday contact such as sharing eating utensils and bathroom facilities or hugging and kissing. (Most scientists agree that while HIV transmission through deep or prolonged "French" kissing may be possible, it would be extremely unlikely.)
Here in the U.S., screening the blood supply for HIV has virtually eliminated the risk of infection through blood transfusions. (And you cannot get HIV from giving blood at a blood bank or other established blood collection center.) Sweat, tears, vomit, feces, and urine do contain HIV, but have not been reported to transmit the disease (apart from two cases involving transmission from feces via cut skin). Mosquitos, fleas, and other insects do not transmit HIV.
Does that help alleviate your fear?