Tracking Risk Factors Related to an Outbreak of COVID-19 Among Healthcare Workers in a General Medicine Ward.

Background An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection occurred in a medical ward involving patients and hospital staff from May to June 2020. Aim The aim of this study is to determine risk factors related to the outbreak of SARS-CoV-2 in six healthcare workers (HCWs) in a medical ward with initially unrecognized coronavirus disease 2019 (COVID-19) positive patients. Methods A retrospective cross-sectional study was conducted using a comprehensive questionnaire and personal interviews to determine the risk factors for COVID-19 infection in HCWs. Findings A total of 6/34 HCWs were diagnosed with COVID-19 in a medical ward. There were no differences between COVID-19 negative HCWs and COVID-19 positive HCWs in terms of mean duration of hours worked in the unit during the cluster event (180.2 vs 177.5 hours) (p>0.05), mean total time spent in contact with COVID-19 positive patients (12.8 vs 10.5 hours) (p>0.05), mean total time spent on aerosol-generating procedures (1.9 vs 0.9 hours) (p>0.05), and mean total time spent on non-aerosol generating procedures (10.9 vs 9.6 hours ) (p>0.05). There was no difference in exposure to COVID-19 positive family members among the HCWs (33% vs 3.7%, p=0.08). In contrast, exposure to COVID-19 positive contacts in the community was significantly greater in infected vs non-infected HCWs (16.7% vs 0%, p=0.03). Conclusion There was no significant difference in risk factors for contracting SARs-CoV2 among HCWs due to hospital exposures. COVID-19 positive HCWs were more likely to be exposed to positive individuals in their households and community, indicating that the source of SARS-CoV-2 infection came from outside the hospital.