The largest and most significant difference of Covid–19 hard outcome indicators between Lombardy and Veneto was in the pre-lockdown CFR (Table 1). This indicator has been recently discussed for uncertainties about the real denominator (number of infected subjects), particularly in the initial epidemic period (5,7). The markedly high CFR in Lombardy is likely explained by the low denominator. resulting from the SBCD strategy that can be biased toward detection of more severe clinical cases, as also suggested by the high hospitalization rate in that region. When SBCD was loosened and intense testing for SARS–2-Cov infection was implemented, leading to increased identification and isolation of milder cases and asymptomatic infections (post-lockdown period), the CFR became more reasonable owing to the higher denominator. Notably, Veneto’s CFR, at both timepoints, is remarkably low ( below 1%), close to that assumed to be the “real world” lethality under optimal case detection conditions, efficient contact tracing, quarantine and lack of confounders factors (7).This interpretation is supported by the data of the hospitalization ratio if we assume that a higher number of asymptomatic or minimally symptomatic subjects would not require hospitalization..
It is important putting the above differences in the regional context, and ask as to which of the main regional factors has favoured or hindered RMS strategy. As shown in Table 2, there are important, Covid–19- relevant, similarities between the two regions: both are highly industrialized, with similar average personal income, median population age and life expectancy.However, there are also important differences which could have played a role both in the choice of control strategy and their implementation. In particular the lower population density and the greater number of hospital-integrated territorial health services (8), have certainly favoured RMS implementation in Veneto while making it more difficult to apply in Lombardy, at least in the initial epidemic period when this region may have suffered shortage of testing capability (9). However, the reduction of mortality gap with Veneto when Lombardy increased SARS–2-CoV testing would suggest that RMS implementation was indeed possible also in Lombardy if chosen as suitable strategy at the beginning of the epidemic, and tools for extensive SARS–2-CoV testing had made available. Finally, worse disease outcomes in Lombardy could also be contributed to by a particularly high burden of unrecognized Covid–19 cases before the first official one (9), but this remains undetermined until comparative seroprevalence studies clarify the matter. We are aware that other unknown factors might have played a role, but all this considered, the rather impressive Covid–19 outcome differences between the two regions supports our opinion that RMS strategies, if early implemented, can help control Covid–19 epidemic also in a wide regional context as it does in closed institutional settings or small communities (1–3). Data and considerations made here can help identify and implement the most suitable strategy for the control of present Covid–19 outbreaks in Italy and allow a more effective preparedness for expanded testing, contact tracing and quarantine to control a possible second wave of infections in case specific anti-SARS–2-CoV therapeutics and vaccines are not available.