Risk factors for COVID-19 outbreaks in livestock slaughtering and processing facilities in Republic of Korea.

Background: The goal of this study was to help prevent and control the spread of coronavirus disease 2019 (COVID-19) by identifying transmission routes and risk factors in livestock slaughtering and processing facilities (SPFs) and establishing an optimal intervention strategy for outbreaks.

Methods: This case series study was a demographic analysis of patients with confirmed COVID-19 associated with 5 SPFs in Korea between January and June 2021. Additionally, in a retrospective cohort study, the association between COVID-19 infection and risk factors was analyzed for SPFs at which outbreaks occurred.

Results: The COVID-19 attack rates were 11.2%, 24.5%, and 6.8% at 3 poultry SPFs (PSPFs) and 15.5% and 25.2% at 2 mammal SPFs (MSPFs). Regarding spatial risk factors, the COVID-19 risk levels were 12.1-, 5.2-, and 5.0-fold higher in the refrigeration/ freezing, by-product processing, and carcass cutting areas, respectively, than in the office area. The risk of COVID-19 infection was 2.1 times higher among employees of subcontractors than among employees of contractors. The COVID-19 risk levels were 5.3- and 3.0-fold higher in foreign workers than in native Korean workers in the PSPFs and MSPFs, respectively.

Conclusion: As the COVID-19 pandemic continues, a detailed policy for infectious disease prevention and control intervention is needed, without interrupting economic activities. Thus, we propose an ideal intervention plan to prevent COVID-19 through disinfection and preemptive testing and to block its transmission through effective contact management during outbreaks at SPFs.