The spread of HIV by exposure to infected blood

The spread of HIV by exposure to infected blood usually results from sharing needles, as in those used for illicit drugs. HIV also can be spread by sharing needles for anabolic steroids to increase muscle, tattooing, and body piercing. To prevent the spread of HIV, as well as other diseases including hepatitis, needles should never be shared. At the beginning of the HIV epidemic, many individuals acquired HIV infection from blood transfusions or blood products, such as those used for hemophiliacs. Currently, however, because blood is tested for both antibodies to HIV and the actual virus before transfusion, the risk of acquiring HIV from a blood transfusion in the United States is extremely small and is considered insignificant.

There is little evidence that HIV can be transferred by casual exposure, as might occur in a household setting. For example, unless there are open sores or blood in the mouth, kissing is generally considered not to be a risk factor for transmitting HIV. This is because saliva, in contrast to genital secretions, has been shown to contain very little HIV. Still, theoretical risks are associated with the sharing of toothbrushes and shaving razors because they can cause bleeding, and blood can contain large amounts of HIV. Consequently, these items should not be shared with infected people. Similarly, without sexual exposure or direct contact with blood, there is little if any risk of HIV contagion in the workplace or classroom.