Epidemiology of human immunodeficiency virus infection and acquired immunodeficiency syndrome.

As of December 31, 1988, 82,764 cases of acquired immunodeficiency syndrome (AIDS) and more than 46,000 AIDS-related deaths had been reported in the United States. In 1987, AIDS deaths accounted for 9% of the total mortality among men 25 to 34 years of age. Projections suggest that the impact of human immunodeficiency virus (HIV) infection on morbidity and mortality in young adults and children will continue to increase, with an estimated 50,000 cases projected to be diagnosed in 1989. The mean latency period between infection and diagnosis of AIDS is estimated to be more than seven years, and 78% to 100% of persons infected with HIV are predicted to develop AIDS within 15 years of onset of infection. Rates of seroconversions have been decreasing since 1984 among cohorts of homosexual HIV-seronegative men, and the proportion of AIDS cases among homosexual men is decreasing. In contrast, the proportion of AIDS cases attributed to intravenous drug use is increasing, with 33% of AIDS cases reported in 1988 occurring among intravenous drug users, their sex partners, or children of women who are intravenous drug users or sex partners of intravenous drug users. Worldwide, the differences in the epidemiology of HIV infection and AIDS are primarily due to differences in the proportions of the modes of transmission and in the time in which HIV infection was introduced.