Relationship between population density and COVID-19 incidence and mortality estimates: A county-level analysis

Relationship between population density and COVID-19 incidence and mortality estimates: A county-level analysis Dear EditorSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel single-stranded RNA-enveloped virus primarily transmitted person-to-person by close contact through respiratory droplets and defined as the causal agent of Coronavirus Disease 2019 (COVID-19).To date, more than 100 million cases and 2.1 million deaths associated to the COVID-19 have been reported worldwide, but the impact of disease has been disproportionate in highly dense areas [1] and among vulnerable populations [2,3].In this ecological study, we investigated the relationship between population density and COVID-19 estimates in a countylevel analysis of Sergipe state, Northeast Brazil, a region with the largest concentration of highly vulnerable people in the country.Sergipe has an area of 21,925 km 2 , an estimated population of 2,318,822 inhabitants, and a population density of 105.8 inhabitants/km 2 .The Human Development Index (HDI) is 0.665 and the proportion of illiterate people and those living on per