Explaining COVID-19 contagion in portuguese municipalities using spatial autocorrelation models

Abstract

This paper investigates the pattern of COVID-19 contagion in Portuguese municipalities from March 23rd to April 5th (the exponential phase). We have recurred to spatial autocorrelation models to discuss how the conglomeration of highly infectious spaces has also contributed to infecting neighbouring municipalities. We have used several indicators for the contagion of COVID-19 from the number of infectious individuals to rates of infectious. As explicative variables, additionally to spatial proximity, we also considered population density, the share of the elderly population as well as the length of municipal perimeter/border. Our results show that highly dense municipalities tended to contaminate close areas. Lengthier perimeters also showed a positive effect on the contagious indicators for a given municipality.

Este artigo investiga o patrón de contaxio da COVID-19 nos municipios portugueses entre o 23 de marzo e o 5 de abril (a fase exponencial). Recorremos a modelos de autocorrelación espacial para analizar como a veciñanza de espazos altamente infecciosos tamén contribuíu a infectar os municipios próximos. Utilizamos varios indicadores para o contaxio da COVID-19, desde o número de individuos infecciosos ata as taxas de infección. Como variables explicativas, ademais da proximidade espacial, tamén consideramos a densidade de poboación, a proporción da poboación de persoas maiores e a lonxitude do perímetro/fronteira municipal. Os nosos resultados indican que os municipios altamente densos tenden a contaminar áreas próximas. Os perímetros máis longos tamén mostraron un efecto positivo nos indicadores contaxiosos para un municipio determinado.