The challenge of eradication: lessons from past eradication campaigns.

I APPRECIATE VERY MUCH your invitation for me to participate in this conference, and, as an interested and concerned observer, to offer some hopefully helpful and perhaps provocative thoughts regarding the steadily strengthening tuberculosis control programs which today are so vitally important. I do so not as an expert in the disease, but from the vantage point of one who spent 11 years endeavoring to eradicate a disease, and more recently, from the vantage point of a policy advisor in the Executive Office of President Bush and as Senior Science Advisor in the United States Department of Health and Human Services. In 1980, the World Health Assembly proclaimed the fact that smallpox had been eradicated and that vaccination everywhere could cease. Thus culminated a global campaign which began in January 1967. That year, 46 countries reported smallpox cases. Surveys were to reveal that between 10 and 15 million cases had occurred that year and that 2 million had died. A ten-year goal had been proposed when the program was originally agreed upon by the World Health Assembly. The target was missed, but only by 9 months and 26 days. This was an achievement which was widely hailed because smallpox through history has been by far the most devastating of all diseases, capable of being transmitted in any country and in any season. Before a vaccination became available, everyone eventually contracted the disease and some 25% to 30% died. That threat was removed by the eradication campaign which, in international support, cost, in all, about $8 million per year over 13 years, from its launch to the certification of eradication by a global commission. The savings are estimated to amount to perhaps $2000 million per year. The immediate lesson which many drew from this achievement was that having eradicated one disease and so having demonstrated eradication to be a possible goal, other diseases should be targeted. All manner of candidates have been proposed over the past 15 years, with everything from urban rabies to periodontal disease to tuberculosis receiving mention by one visionary or another. The advocates argue that even if the goal of eradication is not achieved, substantial additional resources will be mobilized by proclaiming this goal and, at the very least, better control of the disease in question will be achieved. This is a very attractive argument, but a dangerously fallacious one as I shall describe. Let me say at the outset that in my opinion, time devoted to debating the feasibility of additional disease eradication projects is, at this time, a futile waste of energy. In fact, it is to me an indication that the wrong lessons have been derived from past eradication campaigns. You may be surprised to know that in fact there have been, so far, seven global campaigns. The smallpox program was the fifth, its four predecessors, which date back to the early part of this century, having failed ignominiously after the expenditure of large sums of money. They left little behind and are now largely forgotten—programs against hookworm, yellow fever, yaws and malaria. Two global eradication campaigns are operative today— programs against polio and Guinea worm. Both are behind schedule and struggling, although there is hope that one, if not both, may eventually succeed. Thus, I will argue the case that, at this time, our attention needs to be focused on well-structured, scientifically sound programs for disease control. Priority must be accorded to those diseases inflicting the heaviest burden globally, and certainly tuberculosis ranks as one of the most important. But why not eradication? Having devoted 11 years to the effort to eradicate smallpox, I can say with feeling that it was a formidable task which only barely succeeded. Yet, all who have looked at candidate diseases would agree that the biological attributes of smallpox and the technology for dealing with it made its eradication far more likely than for any other disease. Here was a disease which produced a severe illness with an abhorrent rash. Diagnosis was no problem. Even illiterate villagers could identify the disease, and politicians and citizens alike were terrified of it. There were no subclinical cases, thus, one could determine immediately where the virus was circulating; laboratory tests were not required. Tracing the