A Study of the Correlation between the Dates of the First Covid Case and the First Covid Death of 25 Selected Countries to know the Virulence of the Covid-19 in Different Tropical Conditions

BACKGROUND: Since December 2019 the highly contagious COVID-19 virus has been spreading worldwide with a rapid spike in the number of deaths. The WHO declared COVID-19 to be a pandemic in March 2020. As of June 2020 it has been 7 months since the first case of COVID-19 was reported in Wuhan, China. So far, COVID-19 has affected more than 24 million people in 215 countries/territories, has caused more than 0.8 million deaths and spread unpredictably quickly among people worldwide. The infection rate in many nations continues to spike. After restraint of the initial outbreak failed, authorities turned to implementing new policies designed to slow the contagion of the virus and the spread of COVID-19 to a manageable rate. This paper presents a systematic analysis to examine in the 25 most affected countries the association between the dates of first death and the first case of the virus to analyse the virulence and also to examine the association between the first case and the virus spread. METHODOLOGY: Data from the WHO website were used. After filtering the data, we calculated the number of days between the first reported case in China and the first reported case in each of the countries, NDFC. Another variable, NDFD, the number of days between the first reported case and first reported case of each country, was also calculated. Then we established the correlation between NDFC and NDFD. Tables are used to show the statistics and charts in order to make the findings clearer. RESULTS: The date of the first death of each country is not dependant on the first case. When NDFC is high, the variable NDFD is homogeneously low. When the variable NDFC is low, the variable NDFD is heterogeneous. The virus could have been mutating and became more virulent during March. The countries with the highest number of deaths are not the most affected countries when analysing the death ratio of cases and population. CONCLUSIONS: COVID-19 has spread unpredictably quickly among people worldwide. In this critical situation, this paper presents a systematic analysis about the infected cases of COVID-19, deaths and association between first case and first death in each country. In order to obtain a true picture it is necessary to analyse the raw date in different dimensions, and at the end of the paper we will show a clear picture about which countries have controlled the virus very efficiently and which countries have been most affected by it to date.