A study of SARS-CoV-2 evolution in Italy: from early days to secondary effects after social distancing

Marco Claudio Traini; Carla Caponi; Riccardo Ferrari; Giuseppe Vittorio De Socio

The flexibility of the model we are using can allow the introduction of the effects of such further control restrictions. Eq. (9) shows how such a measures have been further implemented reducing the contact rate from c(t = t 0 ) = c 0 = 2 day −1 to c(t t 0 ) ≈ 0.4. In this case the reproduction number assumes the limiting values R tically lowered and (probably) one can even see such an effect already at the early stage of the epidemic looking at the recent data on upper panel of Fig. 5 (yellow squares) . The same approach can be applied to evaluate the evolution of an epidemic secondary event at the moment of a partial relaxation of the isolation measures adopted. Our findings manifest an unavoidable occurrence of secondary events, however they can find our countries prepared thanks to the delay obtained in the first phase by means of isolation. The strategy to implement is largely based on technological resources opening a new era of fast screening. For a deeper discussion of the results one wonder if the choice of the moment can influence the secondary event in a substantial way. The need of saving the intense care from a large peak of presence pushes the inertia of the event to produce a long time tail it is very hard to keep isolation for a corresponding period. However one can analyze the effects of shift in time. In Fig. 8 the results of this further analysis. The technological improvement of the screening process remains the relevant mitigation ingredient and the structure of the secondary event does not change enough to suggest a further delay.