An Outbreak of SARS-CoV-2 in a Garment Factory near the Thailand–Myanmar Border, Tak Province, Thailand, August–September 2021

On 16 Sep 2021, Thailand's Division of Epidemiology, was notified of an outbreak of coronavirus disease 2019 (COVID-19) in a garment factory in Tak Province. An outbreak investigation was conducted to determine epidemiological characteristics of cases, identify risk factors associated with infection, and recommend appropriate preventive measures. A review of COVID-19 surveillance data and outbreak reports was performed. An active case finding was conducted among the factory workers. We interviewed the manager and workers of the factory and performed an environmental observation and conducted a case-control study. Logistic regression models were employed. Of 242 workers tested for severe acute respiratory syndrome coronavirus 2 by rapid antigen test kit, 90 (37.2%) were found positive. The attack rate was highest in the sewing department (47.4%) and among female workers (53.8%). The prevalence of asymptomatic infection was 15.6%. One case with pneumonia was found and there were no deaths. Working in the sewing department was a significant risk factor [adjusted odds ratio (OR) 3.15, 95% confidence interval (CI) 1.01–9.79] while mask wearing [adjusted OR 0.34, 95% CI 0.14–0.82] was a protective factor. Overcrowding and poorly ventilated conditions were observed in the workplace. Our investigation confirmed a COVID-19 outbreak in a garment factory. Reorienting the environment and strengthening individual protective measures, such as mandatory mask wearing and physical distancing amongst the workers, are recommended.