Climate affects global patterns of COVID-19 early outbreak dynamics

Gentile Francesco Ficetola; Diego Rubolini

is the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10.1101/2020.03.23.20040501 doi: medRxiv preprint are available with a delay of approx. three months), and spatial variation among areas of the world is generally much stronger than inter-annual variation for the same region (23). As additional predictors, we considered mean human population density (24) (population density hereafter, expressed in inhabitants/km 2 ) and per-capita government health expenditure (health expenditure hereafter) (indicator 'Domestic General Government Health Expenditure (GGHE-D) 5 per Capita in US$; average of 2015-2017 values downloaded from the World Health Organization database at https://apps.who.int/nha/database). Health expenditure was available at country-level only: hence, regions within countries were assigned the same health expenditure value. Finally, it has been proposed that air pollution, and especially fine atmospheric particulate, could enhance the persistence and transmission of coronaviruses (16, 25) . We therefore extracted 10 values of annual concentration (µg/m 3 ) of ground-level fine particulate matter (PM2.5) for 2016 from the NASA Socioeconomic Data and Applications Center (26) , and calculated the mean abundance of PM2.5 for each country/region. We performed all spatial analyses using the raster package in R (27). 15