"Anxious, pleading, pock-deformed faces; the ugly, penetrating odor of decaying flesh; the hands, covered with pustules, reaching out, as people begged for help .... And there was no drug, no treatment that we could give them."
Long after Dr. Donald A. Henderson orchestrated the massive international campaign to rid the world of smallpox, that memory of its victims remained etched in his mind. In his 2009 book Smallpox: The Death of a Disease, he vividly recalled the suffering he saw as he walked through a ward in Dhaka, Bangladesh in 1974.
An American epidemiologist, Henderson served as director of the World Health Organization's Smallpox Eradication Program from 1966 to 1977, the year the last known case was found in Merca, Somalia. Henderson died on Aug. 19 in Towson, Md., from the complications of a hip fracture. He was 87.
Known to all simply as "D.A.," Henderson was a towering figure in the field, renowned among colleagues not only for his part in the triumph over smallpox, the only human disease ever to be wiped off the face of the planet, but for the zeal, creativity and singularity of purpose with which he pursued "Target Zero," the name given to the goal of eradication.
Charismatic, confident, whip smart and self-assured, Henderson took naturally to the leadership positions he would occupy from as early as 1955. Within just two months of his recruitment to the Epidemic Intelligence Service (EIS), the disease-detection branch of the Centers for Disease Control and Prevention in Atlanta, Ga, Henderson suddenly found himself at the helm — at 27, the acting chief of the elite unit.
Thrust into the role after his boss departed for another job, Henderson was "obviously underqualified," as he recalled years later. But he thrived and soon became the CDC's director of viral disease surveillance. Taking after his mentor, EIS founder Alexander Langmuir, Henderson practiced what he called "shoe leather epidemiology," often leaving the office to collect data and conduct interviews in the field. ("The converse type was the office-bound 'shiny pants' epidemiologist,'" he noted.)
Henderson and Dr. Donald Millar, then head of the CDC's smallpox surveillance unit, had instructions from Langmuir to keep an eye on the disease. Believed to have emerged from a rodent virus, smallpox had long been one of the most feared pathogens on the planet, having maimed and killed more than half a billion people over the previous century. Though there hadn't been a case in the U.S. since 1949, the disease continued to kill some 2 million people a year, and Henderson was "deeply concerned" about the potential for an importation.
By 1964, eradication was a real possibility due to a much improved vaccine and developments in technology — namely, the advent of the jet injector, which could give a thousand injections in an hour.
At the time, however, there was no funding to do it. And plans to attack smallpox at its source — countries in Africa and Asia where the disease was endemic — may well have been shelved if not for the failures of a U.S.-funded measles immunization program.
Across Africa, measles was the more pressing concern than smallpox. The highly contagious disease killed some 10 percent of children before their 5th birthday, and death rates during outbreaks could be as high as 25 percent
Deploying a vaccine newly made by the pharmaceutical company, Merck, a U.S.-funded measles immunization program aimed to eliminate the disease from the region within two years. Yet failure to anticipate conditions on the ground led to serious setbacks. Undermanned and over budget, the program needed help, and the Agency for International Development (later renamed USAID) asked the CDC to send additional teams. Henderson, eyeing an opportunity, responded with a proposal: to set up instead a joint smallpox-measles program.
As the historian Elizabeth Etheridge wrote in her book Sentinel for Health: A History of the Centers for Disease Control, that idea "as much as anything else, launched the global smallpox eradication program."
In 1966, Henderson was tapped to take over the global campaign in Geneva, an undertaking many believed would end in failure, as had previous efforts to eradicate yellow fever, yaws and malaria. At points along the way, Henderson himself had his doubts. Civil wars, droughts and famines and the mass movement of refugees — these and more threatened time and again to derail the program.
But he and his army of "eradicators" – everyone from Dr. William H. Foege, who developed the concept of "ring vaccination" that was key to the program's success (and is now being studied for use against Ebola), to the tens of thousands of community health workers who carried out the grand plans — pressed on, putting aside personal comfort and safety to achieve the goal. They managed to do so in just over a decade.
"When there was a problem and you needed help, D.A. was always there with whatever resources were needed," said Dr. Stanley Foster, a 15-year veteran of the smallpox program and the national adviser for Nigeria. "He was a great mentor and an excellent leader," says Foster of Henderson. Blunt and outspoken yet personable, "he was able to reach out to people all over the world."
That included the Soviet Union, which had begun pressing for smallpox eradication in 1958. "The Russians were convinced this was a burden no advanced nation should tolerate," Historian and University of California, Berkeley professor Elena Conis observes in a recent piece for the magazine Distillations. "The proposal was as selfish as it was altruistic; if smallpox didn't exist in poorer or less powerful nations, it wouldn't find its way into more powerful ones."
That the two countries could work together during the darkest days of the Cold War was itself a victory. But the Soviet Union's contribution to the program was more than symbolic. It was critical, Henderson wrote: "Hundreds of millions of doses of high-quality vaccine, young field epidemiologists, and a world-class research and diagnostic laboratory."
In 1977, "target zero" in the books, Henderson became dean of the Johns Hopkins School of Hygiene and Public Health, and made field experience mandatory for epidemiologists in training. But when the nation's attention turned to what other diseases might be eradicated next, he cautioned restraint, arguing that the country had neither the technology nor the commitment to succeed.
"People were proposing all kinds of things for eradication that D.A. did not like," said Dr. Donald Hopkins, who worked on the smallpox eradication program in West Africa before moving to the Carter Center, where he led its efforts to eradicate Guinea worm.
Eventually, Henderson would come around to both polio and Guinea worm, and once convinced of the latter, "he was very supportive," Hopkins added. "That's one reason I'm so sad about this. I so looked forward to him seeing the end of it."
"Dr. Henderson served an instrumental role in smallpox eradication," said CDC director Dr. Tom Frieden. "His impressive career contributed to saving millions of lives and will continue to save lives for generations to come."
And it has inspired others to follow in his footsteps. As Elena Conis puts it, "The eradication of smallpox was a really important proof of concept. It proved that you could eliminate a disease with vaccination alone and that you could do it without vaccinating everybody, and without an enormous amount of money. You could achieve something of this massive scale through coordination, cooperation and scientific expertise."
Elaine Conis was identified as an Emory University historian in an earlier version of this post. She is now a professor at the University of California, Berkeley. The post has been updated.