To practically no one's surprise, the first test of an AIDS vaccine has failed. That the outcome was widely predicted -- and even anticipated -- must not deter future efforts to develop a vaccine. AIDS is one of the worst scourges humanity has suffered to date, and a combination of economics and demographics ensures that it will get worse. Few challenges are more difficult or more urgent.

Acquired Immunodeficiency Syndrome, now known to the world as AIDS, first emerged about 20 years ago. In two short decades, it has claimed about 25 million victims. There are 13,000 new AIDS infections every day, 2,000 of them children under the age of 15. Some 8,500 people die every day of the disease. By 2010, there will be 20 million AIDS orphans in Africa alone. The United Nations estimates that AIDS will kill 46 million people this decade alone in the 53 worst affected countries. The death toll is predicted to rise to 278 million by 2050.

The task of beating the disease is compounded by the grim economic reality of its pathology. Ninety-six percent of the 36.1 million people currently living with the disease's precursor, HIV, live in developing countries where any medical treatment is a luxury. The stigma associated with the disease discourages governments from addressing the problem head on. That failure alone facilitates its spread. The sheer number of the sick and the dying is slowing economic development and compounding the economic and human cost of infection. A cocktail of drugs has been developed that has reduced AIDS deaths by as much as 75 percent, but the treatment costs thousands of dollars, putting it beyond the reach of all but a tiny proportion of the population in the worst-affected areas.