William H. Foege | physician

At a recent tribute to one of his colleagues, Bill Foege spoke of a "golden age of global health," a time when achievements once only imagined were now possible. Characteristically, the epidemiologist credited the arrival of this new era to the work of others—Bill and Melinda Gates, political leaders, and other people in the audience.

Foege decided that to mount an effective response, he would need to think like the virus.

(Brian Smale)

What he did not say was that this celebratory moment could not have arrived without his own extraordinary work. Because arguably more than anyone else, it is Foege who has built the foundation for the recent explosive progress in the field of global health. Attacking a range of illnesses in developing countries, Foege has literally saved millions of lives.

Driven since childhood, Foege was inspired by the life of Albert Schweitzer and the missionary work of an uncle in New Guinea. He was just a teenager when he declared his intention to become a physician in Africa. After serving as an epidemiology intelligence officer in the United States Public Health Service and studying public health at Harvard University, he made good on his boyhood promise, going to Nigeria to care for villagers from a small church in a remote area.

All too quickly, Foege faced the excruciating dilemma that practitioners of public health know all too well. He had signed on to help with the smallpox eradication effort in Nigeria through the U.S. Centers for Disease Control and Prevention. Smallpox was devastating the communities all around him, but there wasn't enough vaccine to go around. Foege decided that to mount an effective response, he would need to think like the virus.

Realizing that the virus was likely to concentrate in busy markets and other crowded settings, he set out to inoculate every person there, even finding and vaccinating visitors. With this innovation, Foege created human shields against the spread of smallpox. The strategy, ultimately adopted globally, is credited with leading to the only successful global disease eradication campaign in history.

Containment. Foege went on to head the CDC's overall smallpox eradication efforts. Then, in 1973, anxious to get back in the field, he went to India to lead the smallpox battle there. Soon he realized that in another six months, smallpox would be contained in the last village where the virus was still active. Against his boss's urgings, he insisted on coming home. "I'm sorry," Foege told him. "But if I'm here in six months, all the credit will go to the foreigners who worked on this campaign, and the credit really needs to go to the Indian people." He went home. By 1979, the World Health Organization declared that smallpox had been eradicated not just in India but worldwide.

Foege's next assignment was no less daunting—or successful. In 1978, the WHO member states committed to immunizing 80 percent of the world's children against a range of childhood diseases by 1990, a huge increase from a starting rate of about 5 percent. By the mid-1980s, immunization rates were still only about 20 percent, so in 1984, WHO and other organizations called on Foege. As director of the Task Force for Child Survival and Development, Foege created a model for collaboration that has been replicated for other global health problems. By keeping the focus on the problem instead of turf wars, he played a central role in boosting immunization rates in the developing world to 80 percent within six years. James Grant, then the director of UNICEF, the United Nations Children's Fund, called the effort "the largest peacetime mobilization in the history of the Earth."

In 1987, Merck & Co. found that a drug used to treat heartworm in dogs was effective in treating river blindness, then such a serious problem in Africa that in many villages all of the men over 40 were blind. At Foege's urging, Merck pledged to supply a form of the drug, ivermectin, for no charge. But the company would do so only if the task force oversaw distribution. Suspicious of the industry, many of Foege's colleagues advised him to reject the conditions.

But Foege had his mind on the victims. He took responsibility for the distribution, and what developed was arguably the first venture into pharmaco-philanthropy. One of the most effective public-private partnerships in global health, it virtually eradicated river blindness. Since then, other such partnerships have tackled drug-resistant tuberculosis, lymphatic filariasis, trachoma, and guinea worm.

Foege, 71, may have started his life's work in a church, but his career has been defined by his belief in scientific solutions to the most difficult problems. His is a world of cause and effect: By understanding the science of the cause, he has proved, man can change the effect. Foege's optimism and passion for global health have infected generations of global health professionals. Now, as a senior fellow with the Bill and Melinda Gates Foundation and with the Carter Center, his influence has spread far beyond the practitioners in his own field.

Jim Yong Kim, one of the 2005 U.S. News Best Leaders, is François Xavier Bagnoud professor of health and human rights at Harvard University.