Optimal COVID-19 infection spread under low temperature, dry air, and low UV radiation

TL;DR

This study identifies specific climate conditions—around 10°C temperature, 5 g/kg humidity, and 80 kJ/m² UV radiation—where COVID-19 spreads more rapidly, using surrogate data tests on global and regional data from early 2020.

Contribution

The paper introduces surrogate data tests to statistically analyze COVID-19 spread preferences under various climate conditions, providing evidence of climate influence on virus transmission.

Findings

COVID-19 more prevalent at ~10°C temperature

Higher spread associated with ~80 kJ/m² UV radiation

No significant correlation with relative humidity

Abstract

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, is currently spreading rapidly throughout the world, causing many deaths and severe economic damage. It is believed that hot and humid conditions do not favor the novel coronavirus, yet this is still under debate due to many uncertainties associated with the COVID-19 data. Here we propose surrogate data tests to examine the preference of this virus to spread under different climate conditions. We find that the disease is significantly (above the 95% confidence level) more common when the temperature is $\sim$10$^\circ$C, the specific humidity is $\sim$5 g/kg, and the ultraviolet (UV) radiation is $\sim$80 kJ/m$^2$. The significance of relative humidity is below the 95% confidence level and does not show a preferred value. The results are supported using global and regional data, spanning the time period from January to July 2020. The COVID-19 data includes the daily reported new cases and daily death cases; for both, the population size is either taken into account or ignored.