Fig. 2. Incidence of vaccine-derived poliovirus serotype 2 (VDPV2) isolates detected between 1 May 2016 and 1 November 2019.

(A) The probability that isolate was seeded after the Switch (1 May 2016) was calculated according to the 95% confidence intervals of the estimated seeding date, estimated by the number of nucleotides of divergence from the poliovirus vaccine strain, in the viral protein 1 gene of the position, assuming a model for the mutation rate (see supplementary materials). (B) For all isolates with >0.9 probability of post-Switch seeding, the color demonstrates whether there was a corresponding mOPV2 campaign within estimated dates of seeding and the same or adjacent country.