Is there really a heterosexual AIDS epidemic in the United States? Findings from a multisite validation study, 1992-1995. Mode of Transmission Validation Study Group.

The objective of this study was to verify the mode of exposure to the human immunodeficiency virus (HIV) among cases who obtained acquired immunodeficiency syndrome (AIDS) through heterosexual contact and to determine the proportion of cases initially reported with no risk but whose exposure may have been heterosexual. Adults aged > or = 13 years with AIDS, diagnosed from 1992 through 1995 with heterosexual risk or no risk at six US study sites (Alabama, California, Florida, New Jersey, New York City, and Texas), were eligible. Heterosexual risk was validated in 82% (1,610/1,952) of the heterosexual cases. Men were more likely than women to have a risk other than heterosexual (24% vs. 13%, chi2 p < 0.01). An HIV risk was identified for 351 (55%) of those cases with no risk, and men were more likely than women to remain without risk (48% vs. 38%, chi2 P = 0.02). Of the 415 men with no risk, 215 (52%) were reclassified: 94 (44%) were men who had sex with men, 61 (28%) were injection drug users, 48 (22%) had a heterosexual risk, and 12 (6%) had other exposures. Of the 219 women with no risk, 136 (62%) were reclassified: 82 (60%) had a heterosexual risk, 47 (35%) were injection drug users, and 6 (4%) had infection associated with transfusion. In conclusion, most cases reported with heterosexually acquired AIDS had valid heterosexual risk exposures.