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Table 4 High-impact research opportunities identified to address key questions and reduce uncertainty in future iVDPV risk estimates

From: Modeling the prevalence of immunodeficiency-associated long-term vaccine-derived poliovirus excretors and the potential benefits of antiviral drugs

Research opportunities

Research questions

Retrospective analysis of global PID registries

- What are the survival prospects of individuals in different PID categories in different income levels (particularly CVIDs) and how are they changing over time?

- How does IVIG treatment affect PID survival?

Expanded and longitudinal screening of PID patients for poliovirus (with reporting of IVIG treatment status for screened PID patients)

- What fraction of patients with different PIDs (CVID, SCID, others) will develop prolonged and chronic excretion if infected with OPV?

- How many prolonged and chronic excretors currently exist globally?

- How does IVIG treatment affect the probability of developing a long-term infection if infected with OPV?

Clinical trials with PAVDs involving long-term excretors

- How effective are individual and combined PAVDs in clearing poliovirus infections?

Systematic detailed reporting of timelines of events for all known long-term excretors

- Does a PID patient who spontaneously recovered from a long-term infection develop sufficient immunity to prevent future long-term infections of the same or other serotypes?

- How does IVIG treatment affect the probability of developing a long-term infection if infected with OPV?

- What is the current survival and excretion status and the estimated time of infection, recovery (if applicable) and death (if applicable) for each known long-term excretor?

Continued follow-up of all identified long term excretors (including after spontaneous recovery from infection )

- Does a PID patient who spontaneously recovers from a long-term infection develop sufficient immunity to prevent future long-term infections of the same or other serotypes?

- Do frequent concurrent enteric infections result in an increased probability of spontaneous recovery from long-term poliovirus infections?

Intensification of searches for PID patients causing apparent iVDPVs isolated from the environment

- Who are the sources of apparent iVDPVs isolated from the environment?

- What are the bounds on current chronic excretor prevalence in countries that stopped using OPV?

Expanded environmental surveillance for apparent iVDPVs

- What are the bounds on current chronic excretor prevalence?

- Can iVDPVs transmit widely?

Modeling of iVDPV introductions into the general population after OPV cessation

- What are the expected consequences of prolonged and chronic excretion beyond OPV cessation?

Expanded stool sampling around known long-term excretors

- Are iVDPVs as transmissible as cVDPVs and WPVs?