Fig. 2: Comparison between the international dissemination model and the data.

A Date of collection of the first Alpha sample submitted to GISAID and corresponding date of submission for the 24 countries submitting Alpha sequences before 31 Dec 2020. Data are shown by purple circles (collection) and green triangles (submission). Median date obtained from the model is indicated by gray circles (collection) and gray triangles (submission). The horizontal bars display the 95% prediction interval over n = 500 simulations. B Median model predicted cumulative number of countries submitting a first Alpha sequence to GISAID compared with observations. In panels A and B, the purple vertical line indicates the date of Alpha international alert (18 Dec 2020). C Alpha incidence in the UK³⁶ and median model-predicted epidemic profile in the UK. Both model predictions and data are rescaled to the sum over the period considered to allow comparing the profiles of the curves. To account for testing delays model predictions are shifted right of one week. The gray colored ribbon represents the 95% credible interval.