Fig. 1: Mobility, genome sampling, case counts and phylogeographical summaries through time for 10 European countries.
From: Untangling introductions and persistence in COVID-19 resurgence in Europe
a, The country-specific Google mobility influx in the 10 countries during 2-week intervals. b, The weekly genome sampling by country used in the phylogeographical analysis. c, For each country, the ratio of introductions over the total viral flow from and to that country (in 2-week intervals) and a monthly normalized entropy measure summarizing the phylogenetic structure of country-specific transmission chains are shown. The posterior mean ratios of introductions are depicted with circles that have a size proportional to the total number of transitions from and to that country and the grey surface represents the 95% highest posterior density (HPD) intervals. The posterior mean normalized entropies and 95% HPD intervals are depicted by dotted lines. These normalized entropy measures indicate how phylogenetically structured the epidemic is in each country, and ranges from 0 (perfectly structured, for example, a single country-specific cluster) to 1 (unstructured interspersion of country-specific sequences across the entire SARS-CoV-2 phylogeny). The introduction ratios and normalized entropy measures are superimposed on the incidence of COVID-19 (daily cases per 106 people) reported for each country through time (coloured density plot). The two vertical dashed lines represent the summer time interval (15 June and 15 August 2020) for which we subsequently evaluate introductions versus persistence (see Fig. 2).
