The transmission of SARS-CoV-2 is likely comodulated by temperature and by relative humidity

Raines, K. S.; Doniach, S.; Bhanot, G.

Quantifying the role of temperature and humidity on the transmission of SARS-CoV-2 has been confounded by a lack of controlled experiments, the sudden rise in detection rates, and changing weather patterns. In this paper we focus our analysis on data from Colombia, which presents unique economic, demographic and geological characteristics that favor the study of temperature and humidity upon SARS-CoV-2 transmission: the weather varies dramatically across five natural regions (from the Caribbean coast and the Amazon rainforest to the Andean mountains), there are no pronounced seasons, there is a central port of entry, the use of public transportation dominates inter- and intracity travel, and indoor climate control is rare. While only controlled experiments can precisely quantify the role of temperature and humidity upon SARS-CoV-2 transmission, we observe significant attenuation of transmission in climates with sustained daily maximum temperatures above 30 degrees Celsius and simultaneous mean relative humidity below 78%. We hypothesize that temperature and relative humidity comodulate the infectivity of SARS-CoV-2 within respiratory droplets.