Mission Impossible?

An international campaign to rid the world of polio has made dazzling progress. But some experts question whether the scourge can ever be eradicated

Their cargo on ice, the health workers inched over cratered roads for several hours to reach the Dinka’s cattle camp in southern Sudan, a region oppressed by civil wars for three decades. The whole camp, down to the scrawniest toddler, walked toward the truck, curious. Sebastiao Salgado, the Brazilian-born photographer known for his beautiful pictures of people in harsh circumstances, recalls the Dinka’s approach as a “big chance.” The tableau would make for an arresting photograph, with spindly palms backdropping spindly villagers who seemed to glow, he recalls, from the gray dung ash they rub on their skin to ward off insects. But it was a big chance in another sense, too, an opportunity to engage in what Salgado calls “essential behavior,” which is to say doing the right thing. The workers bounded out of the truck, collected the children under 5 years of age and gave each of them two drops of the polio vaccine.

Throughout 2001, the now 59-year-old Salgado, wearing a Leica camera around his neck and sometimes a slouch hat on his shaved pate, followed vaccinators in Somalia, the Democratic Republic of Congo, India and Pakistan as, two drops at a time, they immunized thousands upon thousands of children in a coordinated effort to rid the world of polio by 2005. It was 30 years ago that Salgado, a former economist, began photographing people dispossessed of nearly everything but dignity—indentured miners, desert nomads, homeless migrants. He says he couldn’t resist the offer from Unicef, the World Health Organization (W.H.O.) and others behind the polio eradication campaign to document it, for here was a great problem that, unlike many of the world’s ills, is not intractable. “It has been very interesting for me to contribute to a project that would finish with something, to see the end of something,” he says. His polio photographs—appearing in magazines, gallery exhibitions and on a Web site, www.endofpolio.org—have publicized and helped raise money for the eradication campaign, which has already cost $2 billion and will require another $800 million, $275 million of which has yet to be raised.

Wiping out polio may be more difficult than health officials initially hoped, say critics of the campaign, but the progress so far has been profound. In 1988, nine years after the last outbreak in the United States, the W.H.O. set a goal of eradicating polio; in that year alone, some 350,000 people in 125 nations developed the crippling viral disease. By 2001, the last year for which complete figures are available, widespread use of the oral vaccine had helped reduce the toll by more than 99 percent, to fewer than 1,000 cases overall in ten nations: India, Pakistan, Afghanistan, Nigeria, Niger, Somalia, Sudan, Ethiopia, Angola and Egypt. Wild polio virus remains at large generally in poor, densely populated areas or violence-torn places. But health workers have made inroads. In Somalia, warring clans have ceased firing to let vaccinators into villages. In Sudan, volunteers have walked days to deliver doses. Adding to the task’s enormousness, the vaccine should be administered to each child at least three separate times to achieve full immunity. To rid the world of the disease, health officials say, ten million health workers and volunteers will have to vaccinate a billion children.

The strategy is to make virtually everyone immune to polio simultaneously, thus depriving the virus of its only known host. It usually spreads through oral contact with skin contaminated by fecal matter from an infected person. Ingested, the virus causes no symptoms for most people. But in roughly one in 200, usually children, it attacks the central nervous system, causing paralytic poliomyelitis that can affect the legs, arms and breathing muscles. About 5 percent of polio victims die. In the United States, the disease peaked in 1952, with 21,000 people afflicted that year, remembered by many as a dreaded time of iron lungs and shunned public swimming pools. Vaccines tamed the epidemic—first the injectable, killed-virus vaccine developed in 1955 by Dr. Jonas Salk, then the oral vaccine, developed in 1963 by Dr. Albert Sabin. Today’s eradication effort rests on the oral vaccine because it provides broad immunity, is easy to administer and is cheap, only about 10 cents a dose compared with $2 for the injected version.

But, ironically, the oral vaccine, which contains three strains of weakened polio virus, poses a challenge to the eradication effort: the weakened virus can mutate in the human gut into a more virulent form and spread to others, causing poliomyelitis. (For that reason, children in the United States receive only the injectable, Salk vaccine.) Dr. Donald “D.A.” Henderson, the Johns Hopkins University infectious disease specialist who led the successful effort to eradicate smallpox, says the potential for polio outbreaks tied to the oral vaccine is one of several reasons that eliminating the disease entirely might be impossible; he also cautions that people with immune disorders can harbor the virus for years, possibly transmitting it after the inoculation campaign ends. Henderson, who applauds the “great progress made in the efforts to stop transmission,” nonetheless argues for curtailing the eradication campaign and focusing instead on “controlling” the disease. In addition, Henderson, who advises the White House on bioterrorism, suggests that some funds earmarked for eliminating polio entirely might be better spent against AIDS, tuberculosis and malaria, which are far more common than polio in the developing world.

Advocates of polio eradication counter that outbreaks caused by the oral vaccine are extremely rare, with only three documented worldwide since 2000, resulting in fewer than 30 cases of paralysis; to advocates, the question is not whether to continue the campaign but, rather, how to phase out the oral vaccine after poliomyelitis cases disappear. Besides, they say, the success of eradicating polio from the Western Hemisphere (in 1994), from the PacificBasin including China (2000) and from Europe (2002) shows that the same can be done for the rest of the world. Henderson’s “ridiculous” suggestion, says University of Pennsylvania polio expert Dr. Neal Nathanson, is “distracting and demoralizing to all the people working to make that goal a reality.” To give up now, says Dr. Stephen Cochi, director of global immunization at the Centers for Disease Control and Prevention, would be like “snatching defeat from the jaws of victory.”

Salgado, for his part, says it’s cynical to ease up “so close to the edge of finishing.” He admits he’s no expert, but he allies himself with the physicians, vaccinators and others who, as he puts it in his Portuguese-accented English, “are the guys of the good side of the planet.”

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