摘要：Objectives. We assessed the costs, risks, and benefits of possible future major policy decisions on vaccination, surveillance, response plans, and containment following global eradication of wild polioviruses. Methods. We developed a decision analytic model to estimate the incremental cost-effectiveness ratios and net benefits of risk management options for polio for the 20-year period and stratified the world according to income level to capture important variability between nations. Results. For low-, lower-middle-, and upper-middle-income groups currently using oral poliovirus vaccine (OPV), we found that after successful eradication of wild polioviruses, OPV cessation would save both costs and lives when compared with continued use of OPV without supplemental immunization activities. We found cost-effectiveness ratios for switching from OPV to inactivated poliovirus vaccine to be higher (i.e., less desirable) than other health investment opportunities, depending on the actual inactivated poliovirus vaccine costs and assumptions about whether supplemental immunization activities with OPV would continue. Conclusions. Eradication promises billions of dollars of net benefits, although global health policy leaders face difficult choices about future policies. Until successful eradication and coordination of posteradication policies, health authorities should continue routine polio vaccination and supplemental immunization activities. Before the World Health Assembly committed to eradicating wild polioviruses (types 1, 2, and 3) in 1988, 1 these viruses had been paralyzing an estimated 350 000 children per year globally. 2 Policymakers anticipated that vaccination would stop following global eradication of wild polioviruses, similar to the cessation of vaccination that occurred after the eradication of smallpox. 3 Anticipation of large economic savings and demonstrated successful use of the inexpensive and effective trivalent oral poliovirus vaccine (OPV) to eradicate wild polioviruses in the Americas 4 , 5 supported this international commitment. The Global Polio Eradication Initiative to date has reduced the annual burden of disease by more than 99% to less than 2000 cases of paralysis annually 6 and has achieved eradication of wild poliovirus type 2. 7 Currently, wild poliovirus types 1 and 3 remain endemic in only 4 countries (Nigeria, India, Pakistan, and Afghanistan). Recent importations of wild poliovirus into previously polio-free areas 8 , 9 demonstrate the importance of finishing the job of eradication, maintaining high levels of vaccination coverage—at least until successful eradication—and carefully considering the risks, costs, and benefits of alternatives. 10 The Global Polio Eradication Initiative relies on an eradication strategy that disrupts transmission of wild poliovirus by giving susceptible individuals (mainly children) multiple doses of OPV to ensure high levels of immunity. The Global Polio Eradication Initiative uses the live OPV instead of the inactivated poliovirus vaccine (IPV) as its vaccine of choice because of OPV’s substantially lower cost and ease of administration, 11 superior enteric mucosal immunity, 12 and ability to enhance population immunity through spread to nonimmunized individuals. 13 – 15 In addition to routine childhood immunization with OPV, the Global Polio Eradication Initiative conducts supplementary immunization activities (SIAs) in the form of mass vaccination campaigns. Despite its benefits, OPV comes with the relatively rare side effect of vaccine-associated paralytic polio, which does not occur with the more costly IPV. 16 Although relatively small in the context of circulating wild poliovirus, the current estimated global burden of 250 to 500 cases of vaccine-associated paralytic polio annually that would result from extended use of OPV appears large in comparison to no naturally occurring polio cases in a world free of wild poliovirus. 17 Indeed, with the increasing success of eradication and lower risks of importations, despite its relatively higher cost 18 IPV gradually has become the vaccine of choice for routine immunization in many high-income countries that seek to eliminate cases of vaccine-associated paralytic polio while remaining protected from polio. Within the past decade, polio outbreaks also occurred from circulating vaccine-derived poliovirus—outbreaks in which OPV viruses regained neurovirulence and greater transmissibility as they circulated in susceptible populations. 2 , 19 These events provided an even stronger case for coordinated OPV cessation 20 – 24 while raising the question of whether such outbreaks might persist after OPV cessation. 25 Previous studies presented cost-effectiveness analyses for the US domestic polio vaccination program at various points in time 18 , 26 and retrospectively 27 for various other countries 28 – 30 and for global 31 , 32 and regional eradication. 33 However, no studies provide comprehensive estimates of the cost-effectiveness of the numerous posteradication risk management policy options. 34
