An economic analysis of poliovirus risk management policy options for 2013–2052

Duintjer Tebbens et al. BMC Infectious Diseases (2015) 15:389 DOI 10.1186/s12879-015-1112-8 RESEARCH ARTICLE Open Access An economic analysis of poliovirus risk management policy options for 2013–2052 Radboud J. Duintjer Tebbens1*, Mark A. Pallansch2, Stephen L. Cochi3, Steven G.F. Wassilak3 and Kimberly M. Thompson1 Abstract Background: The Global Polio Eradication Initiative plans for coordinated cessation of oral poliovirus vaccine (OPV) after interrupting all wild poliovirus (WPV) transmission, but many questions remain related to long-term poliovirus risk management policies. Methods: We used an integrated dynamic poliovirus transmission and stochastic risk model to simulate possible futures and estimate the health and economic outcomes of maintaining the 2013 status quo of continued OPV use in most developing countries compared with OPV cessation policies with various assumptions about global inactivated poliovirus vaccine (IPV) adoption. Results: Continued OPV use after global WPV eradication leads to continued high costs and/or high cases. Global OPV cessation comes with a high probability of at least one outbreak, which aggressive outbreak response can successfully control in most instances. A low but non-zero probability exists of uncontrolled outbreaks following a poliovirus reintroduction long after OPV cessation in a population in which IPV-alone cannot prevent poliovirus transmission. We estimate global incremental net benefits during 2013–2052 of approximately $16 billion (US$2013) for OPV cessation with at least one IPV routine immunization dose in all countries until 2024 compared to continued OPV use, although significant uncertainty remains associated with the frequency of exportations between populations and the implementation of long term risk management policies. Conclusions: Global OPV cessation offers the possibility of large future health and economic benefits compared to continued OPV use. Long-term poliovirus risk management interventions matter (e.g., IPV use duration, outbreak response, containment, continued surveillance, stockpile size and contents, vaccine production site requirements, potential antiviral drugs, and potential safer vaccines) and require careful consideration. Risk management activities can help to ensure a low risk of uncontrolled outbreaks and preserve or further increase the positive net benefits of OPV cessation. Important uncertainties will require more research, including characterizing immunodeficient longterm poliovirus excretor risks, containment risks, and the kinetics of outbreaks and response in an unprecedented world without widespread live poliovirus exposure. Background Since its launch in 1988, the Global Polio Eradication Initiative (GPEI) spearheaded interruption of indigenous wild poliovirus transmission (WPV) of all 3 serotypes in all but 3 countries (Afghanistan, Pakistan, Nigeria) by 2013 [1]. Since 2013, only serotype 1 WPV (WPV1) transmission has led to any laboratory-confirmed paralytic cases, with no detected indigenous serotype 2 WPV (WPV2) cases since 1999 [2] and no detected serotype 3 * Correspondence: 1 Kid Risk, Inc., 10524 Moss Park Rd., Ste. 204-364, Orlando, FL 32832, USA Full list of author information is available at the end of the article WPV (WPV3) cases since 2012 [3]. However, as long as any WPVs circulate anywhere, they can cause outbreaks in previously polio-free areas that do not maintain high population immunity through intense vaccination [4–6]. This provides further imperative to interrupt global WPV transmission as soon as possible. The live, attenuated oral poliovirus vaccine (OPV) remains the polio vaccine of choice in most countries because of its low costs, ease of administration, and proven ability to interrupt transmission in poor-hygiene settings by inducing good intestinal immunity and secondarily immunizing close contacts of OPV recipients [7]. However, OPV causes very rare © 2015 Duintjer Tebbens et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Duintjer Tebbens et al. BMC Infectious Diseases (2015) 15:389 vaccine-associated paralytic poliomyelitis (VAPP) in recipients and close contacts [7, 8]. Thus, ending all paralytic poliomyelitis disease (i.e., polio) requires global interruption of all WPV transmission and subsequent global cessation of OPV use [9]. In addition to relatively predictable VAPP cases that will stop as soon as OPV use stops, in populations with low immunity to poliovirus transmission, OPV-related viruses can continue to circulate and evolve to eventually acquire similar properties as WPVs, establish widespread transmission, and cause outbreaks of circulating vaccine-derived poliovirus (cVDPV) [8, 10–14]. The potential for cVDPVs motivates the requirement that countries globally coordinate OPV cessation and necessitates efforts to prepare for cVDPV outbreaks immediately after OPV cessation through intense surveillance, development of an outbreak response strategy, and creation of a global OPV stockpile for outbreak response [9, 15]. Moreover, long-term risks of vaccine-derived poliovirus (VDPV) reintroductions from rare chronic excretors with B-cell-related primary immunodeficiencies (i.e., iVDPVs) or intentional or unintentional release of any live poliovirus (LPV, i.e., WPV, VDPV, OPV, or OPV-related poliovirus) imply the need for continued management to ensure containment even after successfully-coordinated OPV cessation [8]. Most high-income countries use the injectable, inactivated poliovirus vaccine (IPV) exclusively for routine immunization (RI), and middle-income countries continue to adopt IPV for RI using a sequential schedule of IPV followed by OPV (IPV/OPV) or using an IPV dose co-administered with the third non-birth OPV dose [16, 17]. IPV remains much more expensive than OPV, but does not come with VAPP or cVDPV risks because it does not contain a LPV [18]. In anticipation of OPV cessation, the GPEI recommends and supports the addition of one IPV dose co-administered with the third OPV RI dose, which will provide some immunity for recipients to the serotypes stopped [19]. IPV generally provides better seroconversion (i.e., “take”) per dose for all three serotypes than OPV and it protects vaccinated individuals from polio [4]. However, IPV does not protect as well as OPV from infections or from participation in asymptomatic fecal-oral poliovirus transmission, and IPV remains untested in i (...truncated)