Conclusions
Of the several attempts to eradicate diseases, all but one has failed. Even the exception, smallpox, barely succeeded despite the many factors favorable to eradication. Whether any eradication effort will ultimately succeed or fail cannot be known with certainty at the time it is launched. Eradication entails risk. Money spent on eradication may not ultimately pay a dividend. Health risks may also exist. If eradication fails and vaccination levels drop after the eradication goal is abandoned, susceptible persons who were previously shielded from infection may become infected at a later age, when the disease can cause greater harm. The risk also exists that, even if eradication succeeds, the disease may be reintroduced by accidental or deliberate release.
The reasons for potential failure of an eradication effort are many. A nonhuman host may not be discovered until the number of infected humans drops to a very low level (as happened with yellow fever). The tools of eradication may be vulnerable to resistance (insecticides and drugs in the case of malaria). Political problems and civil strife may prevent an eradication program from being executed in critical areas where the disease makes its last stand (a problem today for guinea worm). Termination of vaccination may leave populations vulnerable to microbe reintroduction from an unforeseen reservoir or vaccine strain reversion (a risk now facing the poliomyelitis initiative). Another potential reason for failure is the inability to raise the financial resources needed to complete programs that extend beyond expected targets. All eradication programs have experienced serious financial stringencies during the course of their execution.
Most eradication programs to date have been launched as visionary, far-reaching efforts but with vastly incomplete information. Basic epidemiological information and knowledge of the effectiveness and operational constraints of interventions and costs in different settings are often inadequate, and the required monitoring, evaluation, training, and research components of the program may be absent. If a program's administrators lack a careful, probing analysis of the epidemiology of the various candidate diseases or of the technologies available, and if their comprehension of the potential costs and who would bear them is limited, a program is likely to founder, causing a dispirited staff, confused beneficiaries, and donor fatigue and ambivalence. It is crucial that the eradication methodologies and assumptions in those regions of the world that would be most likely to pose the most significant problems be tested and addressed before launching an eradication program and that evaluation and research continue during the program.
Proposals for disease eradication have seldom been brought to the WHA with specific plans, costs, and uncertainties fully laid out. Nor have the expected sources of fiscal support and needed country support been addressed with specific commitments requested of the members. The WHA has only a limited deliberative capacity, and too much cannot be expected of its members in session. However, designated special committees of the WHA can and should be appointed, consisting of both visionary eradicationists and field-experienced public health and social science personnel. The WHA should take up the question of eradication only after the subject has been thoroughly vetted and sufficiently large-scale pilot programs in the most problematic areas have clarified that an adequate understanding of the epidemiology exists and that the appropriate technologies are available.
In the past, members have not voted for a specific program for which all the uncertainties have been laid out and the benefits and costs associated with different outcomes have also been calculated. Nor, with one exception, have they voted for a resolution imposing responsibilities, including financing obligations, on individual states. The next time a proposal to eradicate a disease is presented to the WHA, it should be comprehensive. It should demonstrate why the effort is worth taking, even if the final outcome is uncertain; it should bind states, morally if not legally, to fulfill the pledges needed to see the program through to its completion; and it should prepare contingencies should the eradication effort fail.
