Climate affects global patterns of COVID-19 early outbreak dynamics

Gentile Francesco Ficetola; Diego Rubolini

The clear relationship between COVID-19 growth rate and climate suggests that seasonal climatic variation may affect the spatial spread and severity of COVID-19 outbreaks (14) , as observed for other virus-caused diseases (3, 6) . We thus displayed potential seasonal changes in 5 Covid-19 growth rates by projecting our best model of r 50 in relation to temperature under the average temperature conditions of the current (March) and next (June and September) months (Fig. 1D-E) . 15 SARS-CoV2 shows a substantial rate of undocumented infections that could facilitate the spread of the disease (21) . This may affect our analyses, which are based on the number of confirmed positive cases (8, 9) . In most countries, reported positives largely refer to tested individuals showing Covid-19 symptoms that require hospitalization. Therefore, even though our models cannot capture the (unknown) dynamics of undocumented infections, they provide key 20 information on the geographical variation in the risk of occurrence of symptomatic SARS-CoV2 infections.