Meteorological factors and domestic new cases of coronavirus disease (COVID-19) in nine Asian cities: A time-series analysis

Zonglin He; Yiqiao Chin; Jian Huang; Yi He; Babatunde O. Akinwunmi; Shinning Yu; Casper J.P. Zhang; Wai-kit Ming

The seasonality in the outbreak of respiratory infectious diseases might be due to the seasonal variation of host physiology (susceptibility, individual immunity and herd immunity) (13) , genetics (14) , viral stability (15, 16) and infectivity (17) (18) (19) (20) , latent infectors constantly shedding viruses (21, 22) , and the atmospheric dispersion and trans-ocean inter-continental migration (23) (24) (25) (26) , which are mainly driven by the meteorological factors, including the temperature and humidity (27) . Geological features and latitude play a major role in forming a meteorological pattern. Lowen et al. assumed the seasonality of influenza and Respiratory Syncytial Virus (RSV) epidemics in temperate climates mainly attributable to the low absolute humidity (19) , and the following factors associated with it, namely the low temperature, increased population, and low micronutrient levels (such as low vitamin D levels) (28, 29) . During the winter in temperate zones, the temperature and humidity are low, characterized by dryness and coldness, and viruses are more easily to be transmitted via aerosols than direct or indirect contact, where the low temperature renders the virus viable and stable in aerosols, and on the surface. However, in the rainy seasons of tropical regions, where the weather is hot and wet, the aerosol transmission decreases but the transmission by direct contact increases (30) ; although the high temperature can decrease the stability of the virus and reduce the level of aerosolization of the viral droplet, with the increased temperature, the amount of virus deposited on surfaces increases (31) .