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

Guided by the analysis of the effects due to the technological developments in the screening phase done in the previous sections, on can try to see again their effect in the present secondary event and the results of such an investigation are shown in the lower part of Fig. 7 . One leaves the model evolving till day = 70 (May 1st) within the most strict measures (isolation), the same measures producing the best fit. May 1st one relaxes (partially or totally) the isolation control, the model will evolve following the new initial conditions fixed at that date. The peak of a new (secondary) outbreak appears and its maximum value and duration depend on the rest of the parametrized conditions. Particularly relevant, once again, the value of t I = 1/δ I reached during the transition time to normalcy. Lowering the diagnostic time to t I ≈ 7 hours, or t I ≈ 5 hours has the power to mitigate substantially the secondary events, in particular if one keeps "half isolation" (as schematically designed in Fig. 6 ).