Evidence of the political nature of AIDS prevention became apparent in April. The Clinton administration acknowledged what research has long established; needle exchange programs reduce the spread of HIV infection, serve as a conduit into treatment programs and don't encourage drug abuse. Yet despite the scientific evidence, the federal government would not fund needle exchanges, officials decided.

“It's politics rather than science driving policy,” Dr. Merson said. “It's but another example of why this epidemic continues to grow and be as serious as it is.”

Robert Heimer, Ph.D., whose 1990 study with Edward H. Kaplan, Ph.D., found that needle exchanges reduced HIV infection by 30 percent, also decried the decision. “It is quite clear from the scientific evidence that needle exchanges can slow the transmission of HIV and other infectious diseases as well as serve as a conduit for getting people into substance abuse treatment,” Dr. Heimer said. “The foolishness has gone on long enough. When politics goes ahead of public health everybody suffers.”

Laws governing syringes and needle exchanges vary from state to state. Eight states prohibit dispensing syringes without a prescription and another 10 place restrictions on the sale of syringes without a prescription. In all but a few states, laws barring drug paraphernalia make possession of needles a crime. The 110 needle exchanges operating in the United States do so under a variety of legal conditions. Six states and the District of Columbia have created exemptions to paraphernalia laws to allow needle exchanges. Other states tolerate them and in some states the needle exchanges operate illegally. None of them receive federal funding.