Classification of the infection status of COVID-19 in 186 countries

We analyze the outbreak of COVID-19 in 186 countries on the basis of the SIQR model. We first represent the time dependence of the rate of change of the number of infected individuals by a piecewise quadratic function and determine the parameters for each country by fitting the time dependence of the daily confirmed new cases of the country. We define the status of outbreak in each country by the sign and the deviation from zero of the rate and show that the infection status of each country can be completely classified into nine different states.