[2018-18] Global transmission of COVID-19: A gravity model approach
[2018-18] Global transmission of COVID-19: A gravity model approach Hyungsoo Woo Moon Soul Graduate School of Future Strategy, KAIST Okyu Kwon National Institute for Mathematical Science Jae-Suk Yang Moon Soul Graduate School of Future Strategy, KAIST Abstract This paper aims to describe the spatiotemporal transmission of COVID-19 and examine how various factors in°uence the global spread of COVID-19 using a modi¯ed gravity model. Log- linearizing the model, we run a negative binomial regression with observational data from 22 January 2020 to 31 December 2020. In the ¯rst model, population size and GDP per capita are positively related to the sum of newly con¯rmed COVID-19 cases within a 10-day window; the values for both variables are statistically signi¯cant throughout the study period. However, the signi¯cance of geographic distance varies. When a single geographic source exits in the early stage, the value is statistically signi¯cant. In the intermediate stage, when disease transmission is explosive between countries, the distance loses its statistical signi¯cance due to the emergence of multiple geographic transmission sources. In the containment stage, when the spread of disease is more likely to occur within a country, distance becomes statistically signi¯cant. According to the second model, the government's internal movement control and non- pharmaceutical intervention policy, percentage of the population over 70 years old, and population-weighted density are statistically signi¯cant and are positively related to the inci- dence of COVID-19. By contrast, average monthly temperature, international travel restriction policies, and political regimes are statistically signi¯cant and negatively associated with the dependent variable. Keywords Gravity model; COVID-19; spatiotemporal transmission; socioeconomic factors; government policies.