MANY AMERICANS have a sense that AIDS has been defeated, or at least fought to a draw. One statistic should be enough to undo that impression: This year 5.6 million people will be newly infected with HIV, the virus that inevitably leads to the fatal disease.

To the extent that people in this country are complacent, it's because of new therapies that indeed have dramatically reduced the mortality rates from AIDS. But those therapies remain too costly for most of the world. From the beginning of the epidemic through the end of this year, AIDS is estimated to have claimed some 450,000 lives in North America; this year's total may be below 20,000. But around the world, in this year alone a total of 2.6 million people will die as a result of AIDS, more than in any previous year.

Most of those victims will be poor people living in poor countries, with Africa the hardest hit. Altogether, 95 percent of people with HIV live in developing countries. Again, one statistic brings home the enormousness of the effect. In industrialized countries such as the United States, 90 percent of the population can expect to live past 60; in South Africa, fewer than half will reach that milestone. Life expectancies in southern Africa have actually dropped precipitously in recent years, and AIDS is the principal reason.

This is not one of those problems for which one simple prescription could lead to a happy ending. Given the rate of new infections, the AIDS epidemic almost surely has not peaked. But the U.N. AIDS organization that compiled most of these statistics also points to fruitful areas for continued work. Some developing countries, notably Brazil, have opted to treat their AIDS patients with new therapies despite the expense, and have found benefits not only in human terms but also in reduced costs for hospitalizations and other treatments. Other countries have made progress with aggressive prevention efforts. Still, not enough is being done--in prevention, in treatment, in making drugs available to poor countries or in the search for a vaccine.