Noninjecting drug users who trade sex for drugs or who engage in unprotected sex while under the influence of drugs increase their risk of infection. People can become infected with HBV through sexual intercourse with an infected person or through exposure to an infected person's blood, as may happen when IDUs share needles. NIDA-supported research has shown that the risk of infection by HBV and HCV is extremely high in the first year after beginning injection drug use. One study found overall HCV and HBV prevalences of 76.9 percent and 65.7 percent, respectively, in a group who had been injecting drugs for 6 years or less. This disease is most prevalent in crowded low-income areas with substandard health conditions.
Drug users are from two to six times more likely to contract TB than nonusers.
CDC estimates that in 1996 at least 11 percent of new TB cases were in drug users with noninjecting drug users twice as likely as IDUs to contract the disease. Compared to others with TB, IDUs are more likely to develop the disease in multiple organs and sites, rather than only in the lungs. The geographic distribution of syphilis and gonorrhea infections across the U.S. reflect the geographical distribution of the use of crack cocaine and its associated high-risk behaviors, such as unprotected sex and the exchange of sex for drugs. Among IDUs, the most common cause for medical treatment is skin infection at the site of injection. Complications from these infections range from skin ulcers and localized abscesses to stroke, botulism, tetanus, destruction of lung tissue, and infection of the heart valves.