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Incidence of Nosocomial COVID-19 in Patients Hospitalized at a Large US Academic Medical Center

Educational Objective
To understand the incidence of hospital-acquired COVID-19 at a large US Academic Medical Center
1 Credit CME
Key Points

Question  What is the incidence of hospital-acquired coronavirus disease 2019 (COVID-19) at a large US academic medical center?

Findings  In this cohort study of 9149 patients admitted to a large US academic medical center over a 12-week period, 697 were diagnosed with COVID-19. In the context of a comprehensive and progressive infection control program, only 2 hospital-acquired cases were detected: 1 patient was likely infected by a presymptomatic spouse before visitor restrictions were implemented, and 1 patient developed symptoms 4 days after a 16-day hospitalization but without known exposures in the hospital.

Meaning  These findings suggest that overall risk of hospital-acquired COVID-19 was low and that rigorous infection control measures may be associated with minimized risk.


Importance  Some patients are avoiding essential care for fear of contracting coronavirus disease 2019 (COVID-19) in hospitals. There are few data, however, on the risk of acquiring COVID-19 in US hospitals.

Objective  To assess the incidence of COVID-19 among patients hospitalized at a large US academic medical center in the 12 weeks after the first inpatient case was identified.

Design, Setting, and Participants  This cohort study included all patients admitted to Brigham and Women’s Hospital (Boston, Massachusetts) between March 7 and May 30, 2020. Follow-up occurred through June 17, 2020. Medical records for all patients who first tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse-transcription polymerase chain reaction (RT-PCR) on hospital day 3 or later or within 14 days of discharge were reviewed.

Exposures  A comprehensive infection control program was implemented that included dedicated COVID-19 units with airborne infection isolation rooms, personal protective equipment in accordance with US Centers for Disease Control and Prevention recommendations, personal protective equipment donning and doffing monitors, universal masking, restriction of visitors, and liberal RT-PCR testing of symptomatic and asymptomatic patients.

Main Outcomes and Measures  Whether infection was community or hospital acquired based on timing of tests, clinical course, and exposures.

Results  Over the 12-week period, 9149 patients (mean [SD] age, 46.1 [26.4] years; median [IQR] age, 51 years [30-67 years]; 5243 female [57.3%]) were admitted to the hospital, for whom 7394 SARS-CoV-2 RT-PCR tests were performed; 697 COVID-19 cases were confirmed, translating into 8656 days of COVID-19–related care. Twelve of the 697 hospitalized patients with COVID-19 (1.7%) first tested positive on hospital day 3 or later (median, 4 days; range, 3-15 days). Of these, only 1 case was deemed to be hospital acquired, most likely from a presymptomatic spouse who was visiting daily and diagnosed with COVID-19 before visitor restrictions and masking were implemented. Among 8370 patients with non–COVID-19–related hospitalizations discharged through June 17, 11 (0.1%) tested positive within 14 days (median time to diagnosis, 6 days; range, 1-14 days). Only 1 case was deemed likely to be hospital acquired, albeit with no known exposures.

Conclusions and Relevance  In this cohort study of patients in a large academic medical center with rigorous infection control measures, nosocomial COVID-19 was rare during the height of the pandemic in the region. These findings may inform practices in other institutions and provide reassurance to patients concerned about contracting COVID-19 in hospitals.

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Article Information

Accepted for Publication: July 31, 2020.

Published: September 9, 2020. doi:10.1001/jamanetworkopen.2020.20498

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2020 Rhee C et al. JAMA Network Open.

Corresponding Author: Chanu Rhee, MD, MPH, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, 401 Park Dr, Suite 401, Boston, MA 02215 (crhee@bwh.harvard.edu).

Author Contributions: Dr Rhee had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Rhee, Baker, Resnick, Morris, Klompas.

Acquisition, analysis, or interpretation of data: Rhee, Baker, Vaidya, Tucker, Klompas.

Drafting of the manuscript: Rhee, Tucker, Klompas.

Critical revision of the manuscript for important intellectual content: Baker, Vaidya, Tucker, Resnick, Morris, Klompas.

Obtained funding: Rhee.

Administrative, technical, or material support: Tucker, Resnick, Morris.

Supervision: Baker, Resnick, Morris, Klompas.

Conflict of Interest Disclosures: Dr Rhee reported receiving grants from the Centers for Disease Control and Prevention (CDC) and from the Agency for Healthcare Research and Quality during the conduct of the study and personal fees from UpToDate outside the submitted work. Dr Klompas reported receiving grants from the CDC during the conduct of the study and personal fees from UpToDate outside the submitted work. No other disclosures were reported.

Funding/Support: This work was funded by grants 6U54CK000484-04-02 from the CDC and K08HS025008 (Dr Rhee) from the Agency for Healthcare Research and Quality.

Role of the Funder/Sponsor: The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

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AMA CME Accreditation Information

Credit Designation Statement: The American Medical Association designates this Journal-based CME activity activity for a maximum of 1.00  AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to:

  • 1.00 Medical Knowledge MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program;;
  • 1.00 Self-Assessment points in the American Board of Otolaryngology – Head and Neck Surgery’s (ABOHNS) Continuing Certification program;
  • 1.00 MOC points in the American Board of Pediatrics’ (ABP) Maintenance of Certification (MOC) program;
  • 1.00 Lifelong Learning points in the American Board of Pathology’s (ABPath) Continuing Certification program; and
  • 1.00 CME points in the American Board of Surgery’s (ABS) Continuing Certification program

It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting MOC credit.

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