Johns Hopkins Magazine -- April 2000
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APRIL 2000


Smallpox remains the only disease ever to be erased from the planet. D.A. Henderson recalls how.
Opening photo:
Henderson on the eradication trail.
APRIL 2000
Pioneers of Advocacy

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A Decimating Illness Eradicated
By Melissa Hendricks

Soon after D. A. Henderson became dean of the School of Public Health in 1977, he gave a talk titled "Eradication of smallpox: No science necessary." When faculty members saw the title of his talk, they were appalled. Who was this government bureaucrat coming in to show them how to run a research institution? "I thought they were going to string me up on a pole," chuckles Henderson, who before joining Hopkins directed the World Health Organization's Global Smallpox Eradication Program, from 1966 to 1977.

Smallpox, officially declared eradicated in 1980, was and is the only disease ever to be erased from the planet. Quite an accomplishment for an illness estimated to have killed at least 500 million people in this century alone.

The title of Henderson's talk, he explains today, was tongue in cheek, and based on the misguided direction he was given in his early days at WHO. "What we insistently were told by WHO was that this is purely an administrative job."

Henderson couldn't have disagreed more. So he set out to convince the powers-that-be that research would be integral to improving the efficiency and effectiveness of the eradication campaign. Armed with a modest research budget, he enlisted a team to investigate better alternatives to the lancet that vaccinators had been using with mediocre results. Eventually, their investigation led to the development of a two-pronged needle that deposited the dose of vaccine quickly and efficiently into the superficial skin layers, where it was most effective. The device was simple to use. "We could teach an ordinary villager to vaccinate in 10 minutes," recalls Henderson.

Other research projects led to consistent standards in the manufacture of the smallpox vaccine, and a formulation that included what the researchers determined to be the safest strain of vaccinia, the virus used in the vaccine. Scientists also discovered that smallpox vaccination offered protection for up to 20 years, rather than only three to five years, as was previously believed.

Henderson is the first to admit that administrative matters also posed challenges that needed to be overcome.

"India was the toughest of all," he remembers. There were more than 6 million people in the country at that time and many cases of smallpox. Further, Henderson and his colleagues found that the population was especially mobile, which hampered efforts to contain the virus. So, during a 10-day period in October 1973, Henderson oversaw a mass communication program aimed at identifying smallpox cases in every single village. Health workers visited each village and asked everyone they met if they had seen any cases of smallpox. "The number of cases was unbelievable," says Henderson. In villages thought to have only 500 cases, they found 7,000. He and his colleagues followed the first survey with others.

"By the third search, we went house by house. It involved 120,000 people and 8 tons of paper." A surveillance team would follow up and go immediately to any identified case of smallpox. "They'd keep the person at home, shut the back door, nail it shut. They hired four watchguards, one at each side of the house." Anybody who entered [or left] the house was immediately vaccinated."

Those who worked under Henderson say his brand of leadership was inspiring. "He recruited great people and placed a great amount of trust in those people," says Ken Bloom, who was a public health field worker in the smallpox program in Zaire and Bangladesh. "He created an ethos in that campaign that made everybody feel that they were at the cutting edge of the biggest public health campaign of the century, and that the eyes of the world were on our activities and watching whether we'd succeed or not."