IF EVER there was a demonstration of the power of science, it is the course of the fight billed “Mankind v AIDS”. Until 1981 the disease (though already established in parts of Africa) was unknown to science. Within a decade it passed from being seen as primarily a threat to gay men, and then to promiscuous heterosexuals, to being a plague that might do to some parts of Africa what the Black Death did to medieval Europe. But now, though 1.6m people a year still die of it, that number is on a downward trajectoryÂ, and AIDS rarely makes the headlines any more. How was this achieved?
The answer has two parts: sound science and international co-operation. First, the science. When the Human Immunodeficiency Virus (HIV), which causes AIDS, was isolated in 1983, nobody had much idea how to deal with it. HIV is what is known as a retrovirus (this means it copies its genes into a host’s cell nuclei using a mechanism called reverse transcription) but drugs that had been developed in the past to protect against retroviruses did not work well against it, partly because it is extremely mutable and could thus evolve to avoid their attentions. The breakthrough came in 1996, when a new class of antiretroviral drug called protease inhibitors was launched. These were used in combination with two older drugs that worked in different ways. The combination meant that evolving resistance required the simultaneous appearance of several beneficial (from the virus’s point of view) mutations-which is improbable.
The Economist
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