SARS-CoV-2 outbreak in a Canadian suburban tertiary hospital necessitating full facility closure: a descriptive observational study

Abstract

Background: SARS-CoV-2 can cause outbreaks in community-and hospital-based settings. The aim of this study was to provide a detailed epidemiologic account of a hospital-wide SARS-CoV-2 outbreak and provide a description of case evaluations, transmission networks and the interventions implemented to stem the outbreak. Methods:We conducted a retrospective descriptive study of a hospital-wide SARS-CoV-2 outbreak at the Misericordia Community Hospital (Edmonton) from June 21 to Aug. 14, 2020. We reviewed hospital chart, public health and occupational health records to determine demographics, case type (community-or hospital-acquired), need for critical care and outcome for each case linked to the outbreak (patients, hospital staff, and community and patient visitors). We developed detailed transmission networks using epidemiologic data to determine what variables may have contributed to transmission.Results: Fifty-eight cases of SARS-CoV-2 infection were linked to this hospital outbreak (31 patients, 25 staff members and 2 visitors; 66% female, age range 19-97 years). One patient required critical care, and 11 deaths were recorded (all among inpatients). Most cases were hospital-acquired (91%), and 28% were asymptomatic at the time of diagnosis. The outbreak was composed of 2 clusters driven by protective equipment breaches, premature removal of precautions, transmission in small staff quarters and infection of a staff member after exposure to a wandering patient with dementia and asymptomatic, undetected SARS-CoV-2 infection.Interpretation: A detailed epidemiologic review of this hospital-wide outbreak shows that a SARS-CoV-2 outbreak can involve complex transmission chains and clusters. Multipronged bundled approaches, aggressive contact tracing, and patient and staff prevalence screening are important to help bring such outbreaks under control, along with ongoing vigilance in detecting delayed cases.

Patient and ward related risk factors in a multi-ward nosocomial outbreak of COVID-19: Outbreak investigation and matched case–control study

“…There have been many reports on hospital-based outbreaks of COVID-19 [ 4 , 25 , 27 – 29 , 31 , 39 , 52 – 56 ], however a strength of our report is that it incorporated a case–control study to explore contributing ward and patient-related factors to the acquisition of COVID-19, occurring in a setting without vaccination for any HCWs or patients. Our outbreak has similarities with other COVID-19 nosocomial outbreaks including unidentified cases on a ward [ 39 , 56 ], positive HCWs who may have sub-optimal adherence to IPC measures [ 52 , 54 ], and the role of multi-bedded rooms in SARS-CoV-2 transmission [ 27 , 29 , 31 , 34 , 35 ] Further, our report included patient symptoms, environmental sampling, whole genome sequencing, viral culture and has identified the novel finding of fluid and electrolyte disorders increasing the likelihood of COVID-19 acquisition.…”

“…The risks of nosocomial transmission of viral respiratory infections [1] have been known for many years and have been recognized in the SARS-CoV-2 pandemic [2]. Nosocomial transmission of SARS-CoV-2 has been reported in acute care institutions from many countries, including Canada [3][4][5][6] and highlight how rapidly SARS-CoV-2 can spread across hospital wards. Previous outbreaks have revealed common themes, including (1) significant disruption of health care services, (2) the need to enhance infection prevention and control (IPC) measures (3) the promotion of a culture that IPC is everyone's responsibility and ( 4) that all healthcare workers (HCWs) need vigilance when assessing patients for COVID-19, appropriate donning and doffing of personal protective equipment (PPE), and to ensure appropriate environmental cleaning [7,8].…”