A patient who tested negative for COVID-19 twice in 24 hours is likely the source of Brigham and Women's Hospital COVID-19 outbreak involving more than 50 people last fall, researchers said in an analysis published Feb. 9 in Annals of Internal Medicine.
The Boston-based hospital detected the COVID-19 cluster in September 2020 that ultimately sickened 14 patients and 38 staff members. After the outbreak was contained, researchers conducted an in-depth analysis to understand how the virus spread through the hospital.
Researchers traced the cluster to a patient who tested negative for the virus upon admission and again 12 hours later via polymerase chain reaction testing. The patient had pulmonary disease and received nebulizer treatments — a liquid medication administered as a fine mist patients inhale.
Staff members said the patient coughed frequently and was not speaking clearly, so staff members had to lean in closely to hear. Researchers said this individual likely infected several staff members, along with patients who shared a room with the individual.
Researchers also interviewed 32 sickened staff members and 128 uninfected but exposed employees. They found infected staff were more likely to have:
- Been present while patients received nebulizers
- Interacted with SARS-CoV-2-positive staff members in clinical areas
- Spent more time exposed to COVID-19 patients
- Not have worn eye protection
In at least two cases, staff members also reported getting infected despite wearing proper personal protective equipment.
"Case clusters are the exception rather than the rule in healthcare settings," Michael Klompas, MD, an infectious disease physician and hospital epidemiologist at Brigham and Women's, said in a news release. "But this cluster and others show that if there is a cluster, we can contain it, and that there are multiple proactive measures we can take to decrease the risk of SARS-CoV-2 transmission in hospitals."