The impact of temperature, population size and median age on COVID-19 (SARS-CoV-2) outbreak

OBJECTIVES: This study aims to explore the association between the spread of COVID-19 and external parameters. In this regard, temperature, population size, median age, and health care facilities of 58 different countries are considered as external factors. METHODS: A negative binomial regression model was fitted to identify the associations between the factors and cases of COVID-19 during the study periods. RESULTS: The temperature, population size, and median age are positively associated with the spreading rate of COVID-19. There is no evidence supporting that case counts of COVID-19 could decline in countries with better health care facilities. Also, an empirical model was presented to estimate the number of cases within a country using the external parameters. CONCLUSIONS: It is impossible to express the change in the number of cases for a unit increase in each of the variables because a change in a single variable depends on different values of other variables. However, the findings of this study provide useful implications for the authorities and decision-makers to take specific precautionary measures.