Fig. 1: Historical time series of RSV and hMPV.

Detections of RSV (green) and hMPV (orange) detections in (A) Scotland, (B–F) five public health regions of Canada, and (G) Korea. Y-axis is on square root scale, and the magnitude varies for each location. For annual outbreaks, the lag reported is that which maximizes cross-correlation between the RSV and hMPV pre-pandemic detections. Although British Columbia and Prairies Region in Canada appear to exhibit major/minor biennial outbreaks by visual inspection, available historical data before the pandemic does not go far enough back in time to verify this statistically. See Supplementary Fig. 1 for results from full cross-correlation analysis and Supplementary Fig. 2 for cross-wavelet transform analysis.