Mechanistic theory predicts the effects of temperature and humidity on inactivation of SARS-CoV-2 and other enveloped viruses

Ambient temperature and humidity strongly affect inactivation rates of enveloped viruses, but a mechanistic, quantitative theory of these effects has been elusive. We measure the stability of SARS-CoV-2 on an inert surface at nine temperature and humidity conditions and develop a mechanistic model to explain and predict how temperature and humidity alter virus inactivation. We find SARS-CoV-2 survives longest at low temperatures and extreme relative humidities (RH); median estimated virus half-life is >24 hr at 10 degrees C and 40% RH, but similar to 1.5 hr at 27 degrees C and 65% RH. Our mechanistic model uses fundamental chemistry to explain why inactivation rate increases with increased temperature and shows a U-shaped dependence on RH. The model accurately predicts existing measurements of five different human coronaviruses, suggesting that shared mechanisms may affect stability for many viruses. The results indicate scenarios of high transmission risk, point to mitigation strategies, and advance the mechanistic study of virus transmission.

Automated summary

In this study, the stability of SARS-CoV-2 on inert surfaces under different temperature and humidity conditions was measured, and a mechanistic model was developed to explain and predict how temperature and humidity affect virus inactivation. The results showed that the virus survives longest at low temperatures and extreme humidity, with implications for understanding virus transmission mechanisms and strategies to mitigate transmission risk. The mechanistic model accurately predicted measurements of five different human coronaviruses, suggesting shared mechanisms may affect stability across various viruses.