Our editorial described an HIV prevention program that focuses on behavior change, education on condoms and their use, early diagnosis of sexually transmitted diseases and treatment, and the role of private physicians [1]. Dr. Harris asks about the wider use of HIV testing, including contact tracing. Many states require partner notification, and HIV testing and counseling have been the cornerstone of federally funded HIV prevention programs. The number of HIV tests done in publicly funded HIV counseling and testing sites in the United States increased by 40% from 1 491 715 tests in 1990 to 2 090 635 in 1991, but the number of HIV-positive antibody tests only increased by 3% from 56 064 to 57 879. In 1992, 2 689 056 tests were done but only 55 024 positive persons were found.

It has, nevertheless, been argued that testing and counseling may be highly cost-effective in preventing HIV transmission. Some data suggest that counseling and testing can lead to safer sex practices [2]. However, the optimal strategies for such behavioral intervention remain a topic of intense research [2]. Our editorial recommended a balanced program involving equal emphasis on condom promotion and improved diagnosis and treatment of sexually transmitted diseases.

Dr. Harris notes the apparent success of mandatory HIV screening in Cuba. However, in Cuba, few persons were found to be infected, and they were provided improved medical care as well as "re-education" during a period of incarceration. Even then, the benefits of the Cuban program are far from clear [3].

Widespread screening makes sense only if the results can be expected to have a positive effect on the persons identified or on the health of the public. Until recently, it has been difficult to show major benefits to persons who know they are HIV-positive before they develop clinical illness. There appears to be a benefit for early treatment of HIV infection, including prophylaxis for opportunistic pathogens [4]. Further, strong evidence suggests that antiretroviral therapy given to pregnant women may help reduce the risk to the neonate for acquisition of HIV, and guidelines for prophylactic zidovudine treatment of a selected subset of HIV-infected pregnant women are now available [5].

When curative HIV therapy becomes available, widespread screening will be inevitable and desirable. Our goal must be to create an environment in which patients at risk will choose to be screened.