Outbreak investigation of the novel coronavirus disease 2019 in a factory, Bangpahan District, Phra Nakhon Si Ayutthaya Province during 25 May–4 June 2023

Abstract

Background: On May 29, 2023, the Situation Awareness Team (SAT) of Bangpahan District was notified by Bangpahan Hospital of seven confirmed COVID-19 cases among factory employees in Bangpahan District, Phra Nakhon Si Ayutthaya Province. With approximately 20 closed contacts at risk of infection, the SAT conducted an investigation to confirm the outbreak's diagnosis, describe the extent of the problem, and assess the spread of the disease and infection control. This included suggesting disease control measures in the factory.

Methods: This descriptive epidemiological study reviewed coronavirus infections at a factory in Bangpahan District. The study used medical records from Bangpahan Hospital for 506 relevant patients. Data included illness, onset date, symptoms, disease progression, key laboratory test results, workplace activities, and job nature. Data collection used the Novelcorona 2 interview, gathering general and clinical information. Antigen tests were conducted on all workplace contacts. A cross-sectional cohort (May 25-June 4, 2023) identified infection causes and risk factors through epidemiological and analytical studies.

Results: A total of 26 confirmed cases of infection were identified in the factory. All patients were high-risk individuals with a history of contact with each other while engaging in activities in the factory without wearing face masks. The majority of symptoms of the patients presented with sore throats, coughs, and fevers. This outbreak is most prevalent in the productive line.

Conclusions and Discussions: The initial outbreak of this epidemic was traced to the engineering department, where the patient contracted the infection from a family member. This infection was identified as the Omicron B.1.1.529 variant. The two related contact factors for employee infection are the sharing of meals and smoking among employees, which are combined with the risk of infection increasing by 4.86 times (RR 4.86, 95% CI = 2.51-9.40).