Figure 1

Mortality curves. (a) DPC (dashed) and ISTAT (solid) differential mortality curves (per 100,000 inhabitants) in four example regions; Lombardia, Veneto, Emilia Romagna and Campania. Curves are smoothed with splines, with degree of smoothing selected by generalized cross-validation (see Methods). ISTAT curves “take off” earlier and in some regions are as much as twice as high at their peak—possibly due to many COVID-19 deaths happening at home and/or not being recorded as such in hospitals, especially in the early stages of the epidemic. (b) MAX mortality curves (per 100,000 inhabitants) in the 20 Italian regions, before (top) and after (bottom) the shifts produced by probKMA run with \(K=2\). In the bottom panel, time is marked as a day number (as opposed to a date); this represents the region-specific time of the epidemic unfolding, and corresponds to actual time (starting on February 16 and ending on April 30) only for regions with no shifts, e.g., Lombardia). Curves are again smoothed with splines, with degree of smoothing selected by generalized cross-validation. Lombardia, Veneto, Emilia Romagna and Campania, also shown in (a), are highlighted in color. In all panels, vertical lines mark the dates of the national lock-down (March 9) and of the suspension of all nonessential production activities (March 23). In the bottom panel of (b) vertical lines still show these dates without shifts; stars on the curves mark the lock-down after the region specific shifts.