BACKGROUND: Healthcare personnel and patients are at risk to acquire severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in healthcare settings, including in outpatient clinics and ancillary care areas. METHODS: Between May 1, 2020 and January 31, 2021, we identified clusters of 3 or more COVID-19 cases in which nosocomial transmission was suspected in a Veterans Affairs healthcare system. Asymptomatic employees and patients were tested for SARS-CoV-2 if they were identified as being at risk through contact tracing investigations; for 7 clusters all personnel and/or patients in a shared work area were tested regardless of exposure history. Whole genome sequencing was performed to determine the relatedness of SARS-CoV-2 samples from the clusters and from control employees and patients. RESULTS: Of 14 clusters investigated, 7 occurred in community-based outpatient clinics, 1 in the emergency department, 3 in ancillary care areas, and 3 on hospital medical/surgical wards that did not provide care for patients with known COVID-19 infection. Eighty-one of 82 (99%) symptomatic COVID-19 cases and 31 of 35 (89%) asymptomatic cases occurred in healthcare personnel. Sequencing analysis provided support for several transmission events between co-workers and in 2 cases supported transmission from healthcare personnel to patients. There were no documented transmissions from patients to personnel. CONCLUSIONS: Clusters of COVID-19 with nosocomial transmission predominantly involved healthcare personnel and often occurred in outpatient clinics and ancillary care areas. There is a need for improved measures to prevent transmission of SARS-CoV-2 by healthcare personnel in inpatient and outpatient settings.
Transmission of SARS-CoV-2 in inpatient and outpatient settings in a Veterans Affairs healthcare system