Uncertainty and Sensitivity Analysis of Cost Assumptions for Global Longterm Poliovirus Risk Management

Abstract

The world will stop the use of oral poliovirus vaccines (OPV) after certification of global wild poliovirus eradication, but investments must continue in long-term poliovirus risk management, including some level of use of the inactivated poliovirus vaccine (IPV). The health economic justification of these activities depends on their assumed costs and savings associated with prevented polio cases. We characterize probability distributions for economic inputs of an existing global model of long-term poliovirus risk management. Using a fixed set of 120 realizations of the stochastic model, we estimate the corresponding expected incremental net benefits (INBs) of OPV cessation compared to continued OPV use over a 40-year time period for a large sample of the uncertain cost inputs. We also explore the impact of some specific assumptions about future IPV costs. Cost-related uncertainty substantially influences the INBs for OPV cessation compared to continued OPV use, although nearly all simulations resulted in positive expected global INBs. IPV cost, OPV administration costs, and average treatment costs emerged as the most influential uncertainties. A potential drop in the IPV cost starting in the 2020’s may result in an expected economic benefit of $1.5-4.5 billion mainly due cost savings in higher-income countries, depending on the timing and magnitude of the cost decrease and on whether they apply to combination vaccine products. Cost-related uncertainties may lead to significantly higher or lower expected long-term benefits of polio eradication and OPV cessation, and efforts to further reduce costs, particularly associated with IPV vaccine cost and delivery, will likely yield significant benefits.