Dose-response Relation Deduced for Coronaviruses from COVID-19, SARS and MERS Meta-analysis Results and its Application for Infection Risk Assessment of Aerosol Transmission

Zhang, Xiaole; Wang, Jing

BACKGROUND: A comprehensive understanding of the transmission routes of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is of great importance for the effective control of the spread of Corona Virus Disease 2019 (COVID-19). However, the fundamental dose-response relation is still missing for better evaluating and controlling the infection risk. METHODS: We developed a simple framework to integrate the a priori dose-response relation for SARS-CoV based on mice experiments, the recent data on infection risk from a meta-analysis and the respiratory virus shedding in exhaled breath, to shed light on the dose-response relation for human. The aerosol transmission infection risk was evaluated based on the dose-response model for typical indoor environment. RESULTS: The developed dose-response relation is an exponential function with a constant k in the range of about 6.4×10 (4) to 9.8×10 (5) virus copies, which means that the infection risk caused by one virus copy in viral shedding is on the order of 10 (-6) to 10 (-5). The median infection risk via aerosol transmission with one-hour exposure (10 (-6) to 10 (-4)) was significantly lower than the risk caused by close contact (10 (-1)) in a room of the area from 10 to 400 m (2) with one infected individual in it and with typical ventilation rate 1 ACH (Air Changes per Hour). CONCLUSIONS: The infection risk caused by aerosol transmission was significantly lower than the risk caused by close contact. It is still necessary to be precautious for the potential aerosol transmission risk in small rooms with prolonged exposure duration.