COVID-19 transmission in Mainland China is associated with temperature and humidity: a time-series analysis

Hongchao Qi; Shuang Xiao; Runye Shi; Michael P. Ward; Yue Chen; Wei Tu; Qing Su; Wenge Wang; Xinyi Wang; Zhijie Zhang

A novel finding of this study is the significant interaction between ARH and AT, and COVID-19 transmission. In Hubei province, the interaction between ARH and AT was found to have a positive effect on transmission (0.04, 95% CI: 0.004-0.07). Increased AT (ARH) led to a decreased effect of ARH (AT) on the incidence of COVID-19 in Hubei province. The exact mechanism of the interaction is unclear. One probable reason might be that a combination of low AT and humidity make the nasal mucosa prone to small ruptures, creating opportunities for virus invasion [21] . A previous study observed an interaction between minimum temperature and humidity on influenza [22, 23] There are some limitations in our study. First, some potential risk factors that could impact the incidence of COVID-19 − for example, province-specific social-economic status − were not included in the model. The study period is short, so that it can be assumed that many covariates did not vary substantially during such a short time period. Second, the incidence of COVID-19 in provinces other than Hubei was more likely to be influenced by interventions after the outbreak in Hubei province. In addition, the meteorological data were collected from the Weather Underground for the capital city for each province only, and data accuracy and representativeness can be improved in future studies. Provinces (except for Hubei) had a short study period and included 1 1 many imported cases.