The purpose of this project is to strengthen polio outbreak prevention and response efforts and poliovirus surveillance capabilities.
Since 1988, the Global Polio Eradication Initiative (GPEI) and its partners have made significant progress toward a polio-free world Despite these successes, GPEI still faces challenges in achieving a polio-free world including such as the continued transmission of WPV type 1 (WPV1) and live-attenuated viruses in oral polio vaccine (OPV) used in under-immunized communities reverting into circulating vaccine-derived poliovirus (DPV). There are also challenges in keeping a region (or the world) polio-free after eradication which necessitate sensitive surveillance systems for detection of outbreaks or potential containment breaches of live poliovirus kept at polio essential facilities (PEFs), such as vaccine manufacturing facilities.
Overcoming the challenges above is critical for achieving and sustaining a polio-free world. This proposal will use statistical and mathematical modeling to provide policymakers and stakeholders with a better understanding and the quantification of the impact of different strategies.
To this end, we will develop, calibrate, and validate a mathematical model of poliovirus transmission and immunization that can be used to evaluate the impact of potential surveillance and outbreak response strategies in silico before deploying these strategies in real life. The model will be used to evaluate the impact (e.g., using outcome metrics such as the number of polio infections during a specified time horizon) and cost-effectiveness of various interventions focused on outbreak prevention, detection, and response. We will examine interventions that include the use of surveillance systems, preventive routine immunization, and responsive supplemental immunization. Similarly, the models can be used to evaluate and compare surveillance strategies ensuring sensitivity around poliovirus emergence and containment breaches from PEFs.
The expected outcomes of the project include the following:
1) A detailed (differential-equation-based) poliovirus transmission model that incorporates outbreak prevention and response strategies such as supplemental immunization activities (SIAs) and routine immunization (RI) calibrated to target populations.
2) A better understanding of how to interrupt cVDVP2 outbreaks. The team will evaluate different outbreak prevention and response strategies that vary in characteristics such as the vaccine choice and the coverage of immunization campaigns. We will evaluate these strategies in terms of their cost and effectiveness in preventing cases of poliovirus to make efficient use of limited resources for outbreak prevention and response.
3) A better understanding of how to integrate different types of surveillance to detect poliovirus sensitively. The team will adapt the model to include different types of surveillance systems and investigate how integrated surveillance systems can sensitively detect circulating viruses and PEF containment breaches.
4) Training and education opportunities for students in statistical and mathematical modeling. The project team will provide direct technical guidance to graduate students involved in the proposed work and provide direct technical guidance create an educational case study and game based on the work in this project which will give students the opportunity to gain experience creating models to guide decision-making through an interactive game.
Our interdisciplinary team consists of expertise in operations research, statistics and machine learning, infectious disease modeling, poliovirus eradication efforts, and public health programming, and will also consult with collaborators who have deep expertise and experiences relevant to the project. We will synthesize these model-based findings for policymakers to inform the implementation of immunization and surveillance efforts.