Modeling Poliovirus Surveillance and Immunization Campaign Quality Monitoring Costs for Pakistan and Afghanistan for 2019-2023

Abstract

Background: The Global Polio Eradication Initiative (GPEI) Strategic Plan for 2019-2023 includes commitments to monitor the quality of immunization campaigns using lot quality assurance sampling surveys (LQAS) and to support poliovirus surveillance in Pakistan and Afghanistan.

Methods: We analyzed LQAS and poliovirus surveillance data between 2016 and 2020, which included both acute flaccid paralysis (AFP) case-based detection and the continued expansion of environmental surveillance (ES). Using updated estimates for unit costs, we explore the costs of different options for future poliovirus monitoring and surveillance for Pakistan and Afghanistan.

Results: The relative value of the information provided by campaign quality monitoring and surveillance remains uncertain and depends on the design, implementation, and performance of the systems. Prospective immunization campaign quality monitoring (through LQAS) and poliovirus surveillance will require tens of millions of dollars each year for the foreseeable future for Pakistan and Afghanistan.

Conclusions: LQAS campaign monitoring as currently implemented in Pakistan and Afghanistan provides limited and potentially misleading information about immunization quality. AFP surveillance in Pakistan and Afghanistan provides the most reliable evidence of transmission, whereas ES provides valuable supplementary information about the extent of transmission in the catchment areas represented at the time of sample collection.

Keywords: dynamic modeling; eradication; polio; surveillance.

Figure 1.

Analysis of lot quality assurance sampling (LQAS) coverage in Afghanistan (A, B) and Pakistan (B, D) in 2016–2020*, comparing fraction targeted by supplementary immunization activities (SIAs) versus absolute fraction targeted by LQAS (A, B) and versus relative fraction targeted by LQAS (C, D). *Data as of November 12, 2020 only for SIAs with LQAS monitoring performed (43 of 71 in Afghanistan and 45 of 81 in Pakistan). Abbreviations: LQAS, lot quality assurance sampling; SIA, supplementary immunization activities.