This cohort study evaluates the incidence of nosocomial coronavirus disease 2019 (COVID-19) among patients admitted to a US medical center in the context of a comprehensive and progressive infection control program.

This study describes the detection, mitigation, and analysis of a large cluster of SARS-CoV-2 infections in an acute care hospital with mature infection control policies and discusses insights that may inform additional measures to protect patients and staff.

NCT00618605.

We describe 3 instances of SARS-CoV-2 transmission despite medical masks and eye protection, including transmission despite the source person being masked, transmission despite the exposed person being masked, and transmission despite both parties being masked. Whole genome sequencing confirmed perfect homology between source and exposed persons’ viruses in all cases.

We assessed SARS-CoV-2 transmission between patients in shared rooms in an academic hospital between September 2020-April 2021. 11,290 patients were admitted to shared rooms, of whom 25 tested positive. Among 31 exposed roommates, 12 (39%) tested positive within 14 days. Transmission was associated with PCR cycle thresholds ≤21.