Number of papers published by year on reassortment, analysing all eight influenza A gene segments. * indicates data available for a partial year. Figure S2. Flow diagram showing the criteria for papers being included in the review. The number of papers excluded and included at each stage are indicated on the flow diagram. Figure S3. Inter-subtype reassortant analysis: Odds ratios for reporting inter-subtype reassortants by region, host and year. Crude (red) and adjusted (blue) odds ratios for the rate of reporting novel inter-subtype reassortants by region (a), host (b) and year (c). The dashed line at 1.00 on (a) and (b) represents the baseline level of risk, vertical bars crossing the dashed line indicate no effect at the 5 % level. The vertical lines above and below each point indicate 95 % confidence intervals. Adjusted odds are from the general additive logistic model of region and host as factors and year of isolated as a smooth term (c) [35]. Blue areas of (c) show 95 % confidence interval for smooth t...