Univariable and multivariable analyses of cases (district−6-months where the first AFP case associated with a VDPV2 emergence was detected) vs. controls (district−6-months with no VDPV2 emergence).

<p>Abbreviations: CI, confidence interval; OR, odds ratio; <i>P</i>, p-value. Statistically significant p-values <0.05 are shown in boldface. Borderline significant p-values <0.1 are shown in italics.</p

Risk factors for an emergent VDPV2 to establish a circulating lineage associated with >1 case of poliomyelitis in Nigeria.

<p>Serotype-2 population immunity and DTP3 coverage in districts in the 6-month period when the first AFP case associated with each of the 29 independent VDPV2 emergences in Nigeria during 2004−2014 were reported. Red triangles represent isolates that established circulating lineages, whereas blue circles represent single isolates.</p

Illustration of results from the stochastic dynamic mathematical model of VDPV2 emergence and spread.

<p>The model is simulated for 1 year and a population of 10,000 individuals, starting from a VDPV-free equilibrium that includes routine immunisation. OPV2 withdrawal occurs at 6 months (red arrow) and the last tOPV SIA is assumed to occur 4 weeks before this date in agreement with current plans. SIAs are implemented 4 weeks apart. We define the risk of a VDPV2 outbreak after OPV2 withdrawal as the probability of having >200 incident VDPV2 infections during the 6 months following OPV2 cessation. In this illustration, the grey lines represent the number of VDPV infected individuals over time for 20 different simulations of the model assuming 20% routine immunisation coverage and 3 tOPV SIAs with 80% coverage implemented before OPV2 withdrawal.</p

Additional file 1 of Changes in on-time vaccination following the introduction of an electronic immunization registry, Tanzania 2016-2018: interrupted time-series analysis

Additional file 1: Supplementary Table 1. Comparison of immunization coverage between data sources. Supplementary Table 2. Tanzania immunization schedule primary and adolescent infant vaccination schedule