Until recently, the acquired immunodeficiency syndrome (AIDS) has been considered a disease only of certain specific high-risk groups: homosexual and bisexual men, intravenous drug users, recent Haitian immigrants, hemophiliacs, and persons who had received transfusions of blood or blood products. The primary public health strategy for controlling AIDS was to educate these high-risk groups about the disease and its transmission so that they could reduce their own risk of acquiring and transmitting it. This control strategy implied that AIDS was occurring only within these groups and that it would remain there.
In San Francisco this strategy has been employed for some years with dramatic, sustained changes in high-risk sexual activity among homosexual men. Rectal gonorrhea rates in San Francisco have sharply declined, and other sexually transmitted diseases have shown similar decreases (San Francisco Department of Public Health, unpublished data, June 1985). However, even though the number of high-risk sexual contacts