COVID-19 Outbreaks Linked to Imported Frozen Food in China: Status and Challege.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA contamination was reported on China's imported frozen foods and packaging materials. However, there was no evidence of this disease initiated by environment-to-human transmission until the outbreak of coronavirus disease 2019 (COVID-19) in Beijing in June 2020. This article aimed to analyze and summarize COVID-19 outbreaks related to cold-chain foods to provide a scientific basis for tracing the epidemiological trajectory of the pandemic, providing risk assessments, and mitigation policies. Overall, 37 COVID-19 outbreaks and 5,741 infected cases were reported within the study period. It was found that 7 outbreaks and 689 cases were linked to imported frozen foods. The first index case among the 7 outbreaks was exposed to SARS-CoV-2-contaminated outer packaging of frozen food, triggering the subsequent community transmission. This study supported the speculation that cold-chain foods act as a pathway for SARS-CoV-2 and might present a risk for virus transmission between countries and regions. Handlers and processors exposed to the imported frozen foods should be effectively self-protected, daily monitored for clinical manifestations of COVID-19, and tested for SARS-CoV-2 nucleic acid at regular intervals.