Policy Decision Options During the First 5 Years Following Certification of Polio Eradication

Nalinee Sangrujee, PhD, MPH; Radboud J. Duintjer Tebbens, MS; Victor M. Cáceres, MD, MPH; Kimberly M. Thompson, ScD

In This Article

Abstract and Introduction

Policy makers face a number of difficult choices as they develop policies to ensure maintenance of a polio-free world following global eradication and certification. These policy decisions include choices about immunization, outbreak response (including whether to create a vaccine stockpile), surveillance, containment, management of chronic excretors, and investment in future research. This paper focuses on identifying the categories of decisions and characterizing the actual factors that country-level policy makers must weigh to manage polio risks during the first 5 years after certification. Building on a comprehensive literature review, we report the results of the first qualitative analysis to: (1) systematically characterize each type of decision and the relevant options during the first 5 years after certification, (2) clearly identify critical factors that influence the choices, and (3) specifically demonstrate the interdependence among the decisions to produce a reduced set of decision options. This paper explicitly focuses on the different perspectives of developed and developing countries in characterizing the options. While the management of polio risk in the postcertification period presents important challenges, this comprehensive approach helps simplify the process by focusing on critical decisions.

Successful polio eradication efforts continue to move the world closer to eradication and certification as free of wild poliovirus. Global certification will occur once all 6 World Health Organization (WHO) regions report finding no wild poliovirus under high-quality surveillance for at least 3 years and the Global Certification Commission becomes satisfied that sufficient laboratory containment exists,[1,2] a milestone already achieved by 3 regions. The achievement of polio eradication and certification will soon lead policy makers to face difficult choices to ensure maintenance of a polio-free world. These choices primarily include policies related to: routine and supplemental immunization, outbreak response (including whether to create a stockpile), surveillance, and containment of wild and vaccine-derived polioviruses (VDPVs). The combination of discrete policy choices forms an overall strategy, with the best strategy from the policy maker's perspective striking an optimal balance among the risks, costs, and benefits. In the context of global discussions of postcertification risk management strategies, few efforts to date have comprehensively described the complexity of choices and placed them within the context of developing and evaluating an overall national strategy. This paper builds on prior work to help fill this void.

Recent discussions predominantly focused on stopping immunization as the ultimate goal of the eradication initiative and on characterizing related issues. In March 1998, a WHO meeting on the scientific basis for stopping polio immunizations identified 4 strategies for stopping immunization that depended on the then unanswered question of whether VDPVs could persist in populations.[3,4] If VDPVs could persist, the preferred options would be to replace the current trivalent oral polio vaccine (tOPV) for a transition period or replace the tOPV indefinitely with either the enhanced inactivated polio vaccine (eIPV) or a new vaccine. If VDPVs could not persist, the preferred option involved a coordinated cessation of tOPV use, possibly including sequential removal of eradicated strains from tOPV (ie, using bivalent OPV [bOPV] or monovalent OPV [mOPV]).

Following clear evidence of the persistence of VDPVs and associated outbreaks,[5] Wood and colleagues[6] concluded that "discontinuation of OPV in a synchronized way remains the most plausible" option. Subsequent publications presented similar vaccination options[7,8,9,10,11,12,13] and discussed whether and how immunization should be stopped,[14,15,16] with one study emphasizing the differences in decisions between developed and industrialized countries.[15] Another study summarized available data addressing the option of using monovalent vaccines as part of the immunization policy,[17] and a recent report noted the interdependence of countries' decisions.[18]

In spite of clear recognition of the need for surveillance strategies, stockpiles, and contingency plans to respond to potential outbreaks in the postcertification era,[3,4,9,10,13,19,20] few articles have elaborated on these issues and related decision options.[10,21] Fine and colleagues[10] estimated the impact in the posteradication era of an outbreak in a population assuming various immunization and surveillance conditions that might result from the implementation of different policies. From their analysis of the implications of delays in outbreak response, they recommended: (a) maintaining active surveillance for at least 5 years after ceasing all polio vaccination, (b) minimizing delays in diagnosis and confirmation of an outbreak, (c) restricting poliovirus work to a few high-level containment laboratories, (d) maintaining OPV manufacturing capacity, and (e) establishing a stockpile and a response protocol for outbreaks. Recently, Sangrujee and colleagues[21] estimated the potential immunization policy costs for continuing tOPV, switching to eIPV, and stopping immunizations, and developed general cost estimates for global programmatic activities such as maintaining stockpile, laboratory network, and surveillance capabilities. Finally, Fine[22] suggested the need to refine the scenarios presented by Wood and colleagues,[6] recognizing that probably the most important choice facing policy makers remains which vaccine to use, if any.

While these papers represent important progress in informing decision makers, considerable work remains. The decision makers at the 1988 World Health Assembly (WHA) resolved to eradicate polio,[23] and this paper anticipates that the success of the eradication initiative will lead a future WHA to discuss and determine global polio policies to implement after global certification. Clearly, the current (precertification) time period represents a critical time for research efforts focusing on scientific uncertainties, economics, and logistics to provide sufficient information to decision makers about the implications of policy challenges after certification.

This paper describes the policy options during the first 5 years after certification from the perspective of the decision maker for an individual country. We focus on the first 5 years after certification because it represents a critical time period for decisions about continuing OPV use. During this time, we expect both the highest population immunity and the greatest risk of VDPVs. We characterize the currently debated policy options and discuss how various factors (eg, cost, risks, risk perception, neighboring countries' policies) influence policy decisions. Through qualitative analysis and with the objective of providing focus and context to the debate, we narrow the list of potential policy options to those most likely for decision makers of either developed or developing countries. Section 2 describes the methodology used, while section 3 describes each category of decisions and the current country-level options that exist within that category. Section 4 discusses several factors likely to influence policy makers as they evaluate the options and presents our expectations about the reduced set of options available to decision makers in developed and developing countries. Section 5 discusses critical issues (eg, time); and sections 6 and 7 present the conclusions and references, respectively.


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