PREDICTIVE ANALYSIS OF COVID-19 CONFIRMED CASES IN BRAZIL AND EIGHT COUNTRIES BASED ON THE GOMPERTZ NON-LINEAR MODEL

Abstract

This study aimed to evaluate the progress of Covid-19 confirmed cases in Brazil and in eight countries (Austria, China, Germany, Italy, New Zealand Spain, the United Kingdom and the United States) using the non-linear Gompertz model. The data were obtained in official reports of the World Health Organization (WHO) and were submitted to iterative analysis by least squares method to estimate parameters ,  e  through NLIN procedure (SAS version 9.4). The absolute acceleration obtained by the . The acceleration per day obtained by the third order derivative of the predictive model. The asymptotes correlation with quarantine and with the population density of each country was also verified, in addition to the estimation of the correlation coefficient (R²) using CORR procedure (SAS version 9.4). The predictive model showed that Brazil is on upward curve with tendency to reach 2.226.429 people in total (R²=0.9984). The absolute acceleration showed an increase and the acceleration per day demonstrated that only Brazil is in accelerated movement of cases and the tendency is that it will start to decrease after July 4th. The correlations suggest that the quarantine effectiveness isn’t related to its extension (days), since countries with higher population density showed decrease in cases in a shorter restriction time.