Fig. 4: Relationship between epidemic severity and viral effective population size, and the estimated time to maximum NPI.

a Cumulative deaths within a month following max NPI versus time to max NPI. a Viral effective population size (estimated at max NPI) versus time to max NPI. Colours are different for each world region (see Supplementary Fig 4). The grey line indicates the linear regression line (mean fitted values) and 95% confidence interval. CEST central epidemic seeding time, NPI non-pharmaceutical intervention.