The probability of undetected wild poliovirus circulation: Can we do better?

Acute flaccid paralysis surveillance actively detects new paralytic infections caused by wild poliovirus (WPV). However, most WPV infections occur with no symptom. This complicates determining when WPV is eradicated in the context of stopping oral poliovirus vaccine (OPV). Previous studies have used the time since the last paralytic infection as a variable of interest to construct this probability. In this study, we show that more freely available information can be used. In particular, we focus on enriching the computation of the probability of WPV silent circulation with the date of occurrence of the last paralytic infection. We show that this information can for at least one set of conditions have crucial importance for an accurate estimation of the risk of false positive when declaring WPV eradicated. We also look at the importance of this information for optimal dynamic vaccination strategies.