The Origins and Risk Factors for Serotype-2 Vaccine-Derived Poliovirus Emergences in Africa During 2016–2019

Figures

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  Figure 1.. Posterior distributions of the number of emergences per campaign, from the 40 000 sets of model output campaign-assignments; for example, an average of 12 campaigns led to 1 emergence each. Boxplots show the median, upper and lower quartiles, range and outliers.

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  Figure 2.. Attribution of emergences to likely campaigns: the height of the correspondingly colored section of a bar represents the probability of an emergence having been caused by the campaign on the x-axis. We show supplementary immunization activities for which the sum of probabilities is ≥ .01. Thus, the bar sections corresponding to a particular color sum to close to one. Each campaign has a unique code as indicated on the x-axis, based on the 3-letter code country, year, and campaign number. Emergence codes are based on place names. Abbreviations: ANG, Angola; CAF, Central African Republic; COG, Republic of the Congo; CHA, Chad; ETH, Ethiopia; MOZ, Mozambique; NER, Niger; NIE/NGA, Nigeria; RDC/NIE, Democratic Republic of the Congo; SDN, Sudan; SOM, Somalia; TOG, Togo; ZAM, Zambia.

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  Figure 3.. A, Posterior probabilities for campaigns with ≥.01 probability of causing the CHA-NDJ-1 emergence, detected in N’Djamena, Chad, in August 2019, with 7 nucleotide changes from Sabin. B, Maps of the location of the candidate campaigns and subsequent detections of the CHA-NDJ-1 lineage in people or the environment, demonstrating possible range of spread. Shaded areas indicate the areas targeted by campaigns. Red points indicate locations of districts of the first 3 detections. Black points indicate subsequent detections. Abbreviation: NGA, Nigeria.

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  Figure 4.. Estimated risks of new emergences, with 95% credible intervals, shown in the shaded areas, given population and immunity levels in children younger than 5 years. These are calculated as described in Supplementary Material Section 4.

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  Figure 5.. Expected distances (km) and times (days) between the causal campaign and the first detection, by country. Distances are between the centroid of the province of the province-supplementary immunization activities and the centroid of the district of first detection.