The Economist explains
The fight against AIDS, 30 years on
ON JUNE 5th 1981 America's Centres for Disease Control and Prevention reported the outbreak of an unusual form of pneumonia in Los Angeles. When, a few weeks later, its scientists noticed a similar cluster of a rare cancer called Kaposi's sarcoma in San Francisco, they suspected that something strange and serious was afoot. That something was AIDS. Since then, 25m people have died from AIDS and another 34m are infected. Yet the war on AIDS is going far better than anyone dared hope. A decade ago, half of the people in several southern African countries were expected to die of AIDS. Now the death rate is dropping. In 2005 the disease killed 2.1m people. In 2009, the most recent year for which data are available, the number was 1.8m. Some 5m lives have already been saved by drug treatment. In 33 of the worst-affected countries the rate of new infections is down by 25% or more from its peak. Even more hopeful is a recent study which suggests that the drugs used to treat AIDS may also stop its transmission (see article). If that proves true, the drugs could achieve much of what a vaccine would.