Epidemiological trends of COVID‐19 epidemic in Italy over March 2020: From 1000 to 100 000 cases.

The coronavirus disease 2019 epidemic started in Italy by the end of January 2020 and, after 1 month, it affected 1049 persons. Based on the Italian Ministry of Health data, we reconstructed the daily course of virus‐positive cases and deaths over March 2020 for the whole of Italy, 19 regions and 2 provinces. From 29 February to 31 March, there was a 100.9‐fold increase in the cumulative number of cases and a 428.6‐fold increase in the number of deaths in Italy. When plotted on a semilogarithmic scale, the curves tended to diverge from linearity with 23%, 16%, and 7% average daily increases during the three decades of March. Similarly, the number of deaths decreased from an average daily growth of 19% over the second decade to 10% over the third decade. The correlation coefficients relating the days to cases or deaths over each one of the three decades approached unity. As inferred from the equations of the regression lines relative to the three decades, the doubling times of cases were 3.4, 5.1, and 9.6 days, respectively. The doubling times of deaths over the second and third decades were 4.9 and 7.0 days, respectively. There was a broad geographic variability, with a striking gradient from the North, where 40.8% of cases and 57.9% of deaths occurred in Lombardy, to the South. On the whole, over March there was a trend to epidemic growth decline but the time for the end of the epidemic will depend on a variety of factors and, at present, it is unpredictable. Highlights: Italy was the first western country to experience the coronavirus disease 2019 (COVID‐19) epidemic.A 100,000‐fold increase in cumulative cases and a 429‐fold increase in the cumulative number of deaths were recorded in Italy over the month of March 2020.Even on a semilogarithmic scale, the curves showing the cumulative numbers of both cases and deaths tended to diverge from linearity.The average daily increases of cumulative cases during the 3 decades of March were 23%, 16%, and 7%, whereas those of deaths during the 2nd and 3rd decades were 19% and 10%, respectively.As inferred from the equations of the regression lines relative to the 3 decades, the doubling times of cases were 3.4, 5.1 and 9.6 days, respectively, whereas the number of deaths doubled every 4.9 days during the 2nd decade and every 7.0 days during the 3rd decade.Drawing morbidity and mortality data individually in 19 Italian regions and 2 provinces showed a broad geographic variability, with a striking gradient from North to South. [ABSTRACT FROM AUTHOR]