In this section we first review general epidemiologic trends in HIV and AIDS and then review data particular to injection drug users.
As of June 1994, AIDS had claimed over 243,000 lives in the United States, and 401,749 cases of AIDS had been reported to CDC. On January 1, 1993, CDC revised its AIDS surveillance case definition for adolescents and adults to include three additional clinical conditions and one laboratory marker of immunosuppression.2 This expansion made for a broader case definition, resulting in a large increase in AIDS cases reported across all subpopulation groups. In 1993, 105,990 new adolescent and adult AIDS cases were reported, representing a 127 percent increase over the 46,791 cases reported in 1992.
There were 5,228 pediatric AIDS cases reported to CDC as of December 31, 1993. In 39 percent of cases, the mother was an injection drug user, and in an additional 17 percent of cases she had sex with an injection drug user. Thus, over half of all pediatric AIDS cases are associated with the HIV epidemic among injection drug users. This is likely to be a lower bound estimate because the risk factors for the mother were unknown for an additional 21 percent of pediatric cases.
In 1992, AIDS had become the eighth leading cause of death in the United States. Among women ages 25 to 44, AIDS was the fourth leading cause of death; for men in this age group, AIDS was the leading cause of death, surpassing unintentional injuries, heart disease, cancer, suicide, and homicide (Centers for Disease Control and Prevention, 1994b). Moreover, in New Jersey and New York, AIDS has been reported to be the leading killer among African American women between the ages of 20 and 40 (Kaplan, 1993). In addition to race, the risk to women also appears to be heavily skewed by social class (Epstein et al., 1993; Hu et al., 1993; Kaplan, 1993; Phillips et al., 1993; Fife and Mode, 1992). As discussed below, the largest recent increases in case reporting were observed for adolescents, women, racial/ethnic minorities, and individuals infected through injection drug use and heterosexual contact.
The dynamic nature of the epidemic is illustrated by the temporal changes in dissemination within the United States. In 1984, two cities—New York and San Francisco—reported half of all AIDS cases in this country; as of December 1993, those two cities accounted for 18 percent of new cases. These two cities have also differed in the distribution of AIDS cases by mode of exposure: in San Francisco the majority of cases are related to men who have sex with men; in New York the majority of cases are related