The Infection Control Team at Brigham and Women’s Hospital (BWH) in Boston, Massachusetts, identified a cluster of coronavirus disease 2019 (COVID-19) cases inside one area of the hospital on September 22, 2020. Following an investigation, the outbreak was linked to COVID-19 diagnoses in 42 employees and 15 patients. No new connected cases have been reported since October 3, 2020, according to a news release from BWH.

To contain the outbreak, the hospital conducted SARS-CoV-2 testing on all inpatients every 3 days in addition to testing patients upon admission and enforcing daily symptom screenings. All potentially exposed staff were tested; exposed staff at high risk for severe COVID-19 were tested every 3 days.

Areas affected by the outbreak (Braunwald Tower 16A and 14CD) were thoroughly cleaned, and the building’s heating, ventilation, and air conditioning systems were tested. Patients who were recently discharged from affected units were contacted and tested.

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Once tests were made available to all staff on the main campus on September 25, 2020, a total of 10,840 tests were performed on 7999 unique employees. This testing resulted in 10,319 results; 58 were positive; of which, 42 were deemed likely to be associated with the cluster, 14 were deemed not to be associated with the cluster, and 2 are under investigation. These results indicate that the prevalence of COVID-19 inside BWH (0.18%) was lower than the surrounding community at the time (0.8%).

The infection control team within the hospital identified several factors that contributed to the outbreak, including:

  • A highly infectious source patient
  • Multiple affected individuals who had high viral loads
  • Inconsistencies in patients wearing masks
  • Inconsistencies in providers wearing eye protection
  • Lack of physical distancing among staff while eating

To prevent another outbreak, BWH has implemented measures to counteract the causes of the original cluster. The hospital is reinforcing masking rules for both patients and providers, providing additional break room space for staff to eat while social distancing, and reviewing its contact tracing protocol. To address the issue of inconsistent eye protection, BWH is introducing higher-quality eye protection — the hospital stated this initiative was underway prior to the outbreak — and increasing communication about the importance of eye protection for providers.

“The cluster did not impact any other areas of the hospital or our outpatient clinics, and our experience over the past few months demonstrates that we can create and maintain a safe environment by adhering to all of the elements of our Safe Care Commitment and our infection control policies,” hospital officials stated.


Statement for media regarding COVID-19 cluster [news release]. Boston, MA: Brigham and Women’s Hospital; October 16, 2020. Accessed October 20, 2020.