Analysing and comparing the COVID-19 data: The closed cases of Hubei and South Korea, the dark March in Europe, the beginning of the outbreak in South America

Stefano De Leo; Gabriel Gulak Maia; Leonardo Solidoro

we find the angular coefficient alpha for each country for that time frame. This give us information about how fast COVID-19 spreads with time, consequently allowing us compare the spreading rate for different countries. The β term is the number of infected people at the beginning of the time span covered by the model. What we did then was to select five consecutive days and compute the TCCpM of each, fitting these data to a linear model from which we extract the α-factor. After this we pair this α-factor to the TCCpM calculated at the center of the time period and then move to another ensemble of five days and repeat the process. This provides us with a correlation for how fast COVID-19 spreads as more people are infected. In Fig. 3 (a) the α-factor is plotted for the 10 European countries, Hubei, and South Korea as a function of the TCCpM. The behaviour of the Hubei and South Korea's curves, clearly shows that the α factor after reaching its maximum value goes to zero, closing the outbreak. It is also indicative that for South Korea, where the disease was soon taken at its beginning and the measures adopted timely, we found only a maximum (reproducing the well know Gaussian behaviour) while for the Hubei we find two local maxima. The double peak phenomenon is also found for the European countries. After an initial increase, the European curves start to develop in a more horizontal fashion, indicating the infection rate to approach a more linear growth. This horizontal development is not that of a constant, obviously, which would firmly indicate a linear growth, but it reveals slowing down of the spreading rate with the number of confirmed infections. For Italy, the α factor is in its decreasing region after the double peak. Fig. 3 (b) allows a more detailed look at the α-factor from 0 to 500 TCCpM. At 500 TCCpM Switzerland starts to increase substantially compared to the other European countries. Let us understand the importance of this fact by comparing Switzerland with Italy. At the day 55 (16 March), Italy (with 27980 confirmed cases) has a TCCpM of 462.6 with an α factor of 59.3. Italy in that moment was adopting very restrictive preventing measures. At the day 58 (19 March) Switzerland (with 4075 confirmed cases) reaches 471.7 of TCCpM with an α factor of 116.0 almost twice greater.