HIV seroincidence among patients at clinics for sexually transmitted diseases in nine cities in the United States

Although the numbers of newly reported diagnoses of AIDS decreased in the 1990s it is not clear whether they reflect a decreasing number of new HIV infections, Direct measurement of HIV incidence through follow-up cohort studies is difficult and costly. We estimated HIV incidence and trends in incidence among men who have sex with men (MSM) and heterosexual men and women at clinics for sexually transmitted diseases (STDs) by using a recently developed serologic testing algorithm that requires only a single blood specimen. Cross-sectional anonymous serosurveys were conducted at 13 STD clinics in nine cities in the United States from 1991 through 1997. Before anonymous HIV testing, demographic and clinical information was abstracted. Of 129.774 specimens tested, 362 (0.28%) were from persons estimated to be recently infected, Incidence among MSM was 7.1% (95% confidence interval (CI): 4.8-10.3). 14 times higher than that among, heterosexuals. which was 0.5% (CI: 0.4-0.7). Incidence among MSM and heterosexuals remained unchanged during the time studied. Decreasing rates of new AIDS diagnose,, in the 1990s do not reflect stable rates of new HIV infections among, MSM and heterosexual patient,,, attending these clinics.