Effect of diurnal temperature range on SARS-CoV-2 lifetime

Epidemiological studies indicate that the daily mean temperature and the diurnal temperature range (DTR) are inversely correlated with the likelihood of SARS-CoV-2 transmission. These statistical studies rely on transmission data obtained after the disease has spread across various climates; the results do not provide a physical understanding of virus lifetime. On the other hand, reaction kinetics models have only been used to describe the effect of constant-temperature surroundings on virus lifetime and do not address the inverse correlation between virus lifetime and DTR. This study provides a framework, based on the rate law and Arrhenius equation, for modeling virus lifetime in an environment with a time-varying temperature profile. The virus inactivation rate has an exponential dependence on temperature, which causes temperature fluctuations above the mean temperature to increase the instantaneous rate of inactivation to a greater extent than identical fluctuations below the mean. This asymmetric behavior results in shorter virus lifetimes, offering an explanation for the inverse correlation between the number of COVID-19 cases and DTR, and indicating that regions with similar daily mean temperatures may have different virus transmission rates depending on DTR.