Risk factors and on-site simulation of environmental transmission of SARS-CoV-2 in the largest wholesale market of Beijing, China

Abstract

From June 11, 2020, a surge in new cases of coronavirus disease 2019 (COVID-19) in the largest wholesale market of Beijing, the Xinfadi Market, leading to a second wave of COVID-19 in Beijing, China. Understanding the transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the personal behaviors and environmental factors contributing to viral transmission is of utmost important to curb COVID-19 rise. However, currently these are largely unknown in food markets. To this end, we completed field investigations and on-site simulations in areas with relatively high infection rates of COVID-19 at Xinfadi Market. We found that if goods were tainted or personnel in market was infected, normal transaction behaviors between sellers and customers, daily physiological activities, and marketing activities could lead to viral contamination and spread to the surroundings via fomite, droplet or aerosol routes. Environmental factors such as low temperature and high humidity, poor ventilation, and insufficient hygiene facilities and disinfection practices may contribute to viral transmission in Xinfadi Market. In addition, precautionary control strategies were also proposed to effectively reduce the clustering cases of COVID-19 in large-scale wholesale markets.

Cold chain logistics: a possible mode of SARS-CoV-2 transmission?

“…2 A subsequent study using field investigations and onsite simulations at Xinfadi market suggested the virus could spread from contaminated goods to humans, and environmental factors such as low temperature and high humidity, poor ventilation, and insufficient hygiene facilities and disinfection practices might contribute to viral transmission. 3 A further cluster of cases was reported in July 2020 in Dalian, China, the first of which was in an employee of a cold chain food company. 4 No local infections had been reported in Dalian for 111 consecutive days before this case was confirmed.…”

Strengthening Community Defenses to Prevent and Control the Spread of COVID-19 in China

“…People working in the cold chain or receiving deliveries are at risk of infection. A previous study suggested that poor ventilation and insufficient hygiene facilities may increase the risks of infectious disease outbreaks ( 6 ). Supermarkets, shopping malls, restaurants, and other public places have a large flow of people, but code scanning and body temperature measurement under normal epidemic prevention and control conditions are not carefully implemented.…”

Field Simulation of Aerosol Transmission of SARS-CoV-2 in a Special Building Layout — Guangdong Province, China, 2021

“…In addition, when people walked around, they will influence the airflow and spread fluorescent microspheres to other places. It has also been confirmed that human activities can affect bacteriacarrying particles in a study (8). After simulating breathing and coughing or sneezing of infected persons, fluorescent microspheres can persist in the air and the particle sizes were mainly between 0.3 μm and 0.5 μm.…”

“…Some fluorescent microspheres can settle to the surface of tables, windowsills, and other objects after coagulation. Presently, the research on SARS-CoV-2 transmission usually focused on the simulation cabin experiment or computational fluid dynamic model ( 9 - 10 ). This result provided a basis for epidemic prevention and control and experimental support for future research.…”