Potential Pitfalls of Elimination and Eradication Campaigns

CASE 1 Eradicating Smallpox *

ABSTRACT

Geographic area: Worldwide

Health condition: In 1966, there were approximately 10 million to 15 million cases of smallpox in more than 50 countries, and 1.5 million to 2 million people died from the disease each year.

Global importance of the health condition today: Smallpox has been eradicated from the globe, with no new cases reported since 1978. However, the threat of bioterrorism keeps the danger of smallpox alive, and debate continues over whether strains of the disease should be retained in specified laboratories.

Intervention or program: In 1965, international efforts to eradicate smallpox were revitalized with the establishment of the Smallpox Eradication Unit at the World Health Organization (WHO) and a pledge for more technical and financial support from the campaign’s largest donor, the United States. Endemic countries were supplied with vaccines and kits for collecting and sending specimens, and the bifurcated needle made vaccination easier. An intensified effort was led in the five remaining countries in 1973, with concentrated  surveillance  and containment of outbreaks.

Cost and cost-effectiveness: The annual cost of the smallpox campaign between 1967 and 1979 was $23 million. In total, international donors provided $98 million, while $200 million came from the endemic countries. The United States saves the total of all its contributions every 26 days because it does not have to vaccinate or treat the disease.

Impact: By 1977, the last endemic case of smallpox was recorded in Somalia. In May 1980, after two years of surveillance and searching, the World Health Assembly (WHA) declared that smallpox was the first disease in history to have been eradicated.

The eradication of smallpox—the complete extermination of a notorious scourge—has been heralded as one of the greatest achievements of humankind. Inspiring a generation of public health professionals, it gave impetus to subsequent vaccination campaigns and strengthened routine immunization programs in developing countries. It continues to be a touchstone for political commitment to a health goal—particularly pertinent in light of the United Nations’ Millennium Development Goals (MDGs).

But the smallpox experience is far from an uncomplicated story of a grand accomplishment that should (or could) be replicated. Although the story shows how great global ambitions can be realized with leadership and resources, it also illustrates the complexities and unpredictable nature of international cooperation.

THE DISEASE

Smallpox was caused by a variola virus and was transmitted between people through the air. It was usually spread by face-to-face contact with an infected person and to a lesser extent through contaminated clothes and bedding.

Once a person contracted the disease, he or she remained apparently healthy and noninfectious for up to 17 days. But the onset of flulike symptoms heralded the infectious stage, leading after two or three days to a reduction in fever but to the appearance of the characteristic rash—first on the face, then on the hands, forearms, and trunk. Ulcerating lesions formed in the nose and mouth, releasing large amounts of virus into the throat.

Nearly one third of those who contracted the major form died from it, and most of those who survived—up to 80 percent—were left with deeply pitted marks, especially on the face. Many were left blind. In 1700s Europe, one third of all cases of blindness were attributed to smallpox. 1

POSSIBLE ERADICATION?

In 1798, Edward Jenner announced success in vaccinating people against the disease and went on to claim that his vaccine was capable of eradicating it. 2  With the development in the 1920s of an improved vaccine, mass vaccination programs became theoretically viable. Subsequently, national programs—including the Soviet Union’s experience in the 1930s—showed that eradication was possible. However, it wasn’t until the early 1950s that eradication became a practical goal, with the development of a vaccine that did not require cold storage and could be produced as a consistently potent product in large quantities.

In its earliest form, the idea of a global effort to eradicate smallpox was far from popular. In 1953, the World Health Assembly (WHA)—the highest governing body of the WHO—rejected the notion that smallpox should be selected for eradication. In 1958, however, the deputy health minister of the Soviet Union and delegate to the WHA, Professor Viktor Zhdanov, proposed a 10-year campaign to eradicate the disease worldwide, based on compulsory vaccination and revaccination—and he promised that the Soviet Union would donate 25 million vaccine doses to initiate the program. A year later, a WHO report on the proposal suggested that eradication could be achieved by vaccinating or revaccinating 80 percent of the people in endemic areas within “four to five years.” The Russian proposal was passed in 1959.

Smallpox was a suitable candidate for eradication for several reasons. The disease was passed directly between people, without an intervening vector, so there were no reservoirs. Its distinctive rash made it relatively straightforward to diagnose, and survivors gained lifetime immunity. The relatively long time between contracting it and becoming infectious meant that an epidemic took a while to take hold—and because sufferers were likely to take to their beds as they became infectious, due to the severity of the symptoms, they tended to infect few others. Good vaccination coverage, it was reasoned, would disrupt transmission entirely; where an outbreak occurred, the natural course of the disease gave health workers time to isolate victims, trace contacts, and vaccinate the local population.