Fig. 6: Effective reproduction number \({\mathcal{R}}(t)\) and epidemicity index e(t) for the first wave of the COVID-19 pandemic in Italy.

a Hospital admissions (March to November 2020). Green empty dots represent the curated data that has been used¹⁴ to calibrate the SEPIAR model (the black line and black shading are the median and the 95% confidence interval, respectively, of 2000 simulations with parameter values drawn from a posterior distribution estimated from data). The SEPIAR model has been run until the end of July for validation. Purple shading shows data not used for calibration. b Temporal dynamics of the effective reproduction number obtained from SEPIAR (red curve: median; red shading: 95% confidence interval). Also shown (yellow dots) is the timeseries of effective reproduction numbers and their confidence interval (yellow shading) as published by ISS⁵¹. c Effective epidemicity index (blue curve: median; blue shading: 95% confidence interval) computed from SEPIAR (“Methods”).