ABSTRACT
The challenges facing humanity due to the COVID-19 pandemic require great efforts of researchers for constant monitoring of its dynamics through user-friendly interfaces, adequate mathematical modeling, and long-term forecasting. To estimate the effectiveness of vaccinations, treatment, quarantine restrictions and testing levels, the daily and accumulated numbers of cases and deaths per capita were used for different days and time periods. The linear correlation of relative accumulated values with some demographic characteristics such as population of European countries and regions of Ukraine, its density, and the percentage of people living in cities was investigated. The results have demonstrated that the urbanization level affects the numbers of deaths per capita and the deaths per case ratio. Two opposite trends were revealed for European countries and the regions of Ukraine. The average daily number of cases and deaths in the period from September to December 2020 were compared with the same period in 2021 for Ukraine, EU, the UK, USA, India, Brazil, South Africa, Argentina, and in the whole world in order to find some correlations with seasonal factors, the percentage of the fully vaccinated people and boosters. The results showed that existing vaccines cannot prevent new infections, but vaccinations can diminish the numbers of death per capita. © 2022 IEEE.