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Clinical Characteristics of Patients With Coronavirus Disease 2019 (COVID-19) Receiving Emergency Medical Services in King County, Washington

Educational Objective
To understand the clinical characteristics of patients with COIVD-19 receiving emergency medical services
1 Credit CME
Key Points

Question  What is the clinical presentation to emergency medical services among persons with coronavirus disease 2019 (COVID-19)?

Findings  This cohort study of 124 patients with COVID-19 revealed that most patients with COVID-19 presenting to emergency medical services were older and had multiple chronic health conditions. Initial concern, symptoms, and examination findings were heterogeneous and not consistently characterized as febrile respiratory illness.

Meaning  The findings of this study suggest that the conventional description of febrile respiratory illness may not adequately identify COVID-19 in the prehospital emergency setting.


Importance  The ability to identify patients with coronavirus disease 2019 (COVID-19) in the prehospital emergency setting could inform strategies for infection control and use of personal protective equipment. However, little is known about the presentation of patients with COVID-19 requiring emergency care, particularly those who used 911 emergency medical services (EMS).

Objective  To describe patient characteristics and prehospital presentation of patients with COVID-19 cared for by EMS.

Design, Setting, and Participants  This retrospective cohort study included 124 patients who required 911 EMS care for COVID-19 in King County, Washington, a large metropolitan region covering 2300 square miles with 2.2 million residents in urban, suburban, and rural areas, between February 1, 2020, and March 18, 2020.

Exposures  COVID-19 was diagnosed by reverse transcription–polymerase chain reaction detection of severe acute respiratory syndrome coronavirus 2 from nasopharyngeal swabs. Test results were available a median (interquartile range) of 5 (3-9) days after the EMS encounter.

Main Outcomes and Measures  Prevalence of clinical characteristics, symptoms, examination signs, and EMS impression and care.

Results  Of the 775 confirmed COVID-19 cases in King County, EMS responded to 124 (16.0%), with a total of 147 unique 911 encounters. The mean (SD) age was 75.7 (13.2) years, 66 patients (53.2%) were women, 47 patients (37.9%) had 3 or more chronic health conditions, and 57 patients (46.0%) resided in a long-term care facility. Based on EMS evaluation, 43 of 147 encounters (29.3%) had no symptoms of fever, cough, or shortness of breath. Based on individual examination findings, fever, tachypnea, or hypoxia were only present in a limited portion of cases, as follows: 43 of 84 encounters (51.2%), 42 of 131 (32.1%), and 60 of 112 (53.6%), respectively. Advanced care was typically not required, although in 24 encounters (16.3%), patients received care associated with aerosol-generating procedures. As of June 1, 2020, mortality among the study cohort was 52.4% (65 patients).

Conclusions and Relevance  The findings of this cohort study suggest that screening based on conventional COVID-19 symptoms or corresponding examination findings of febrile respiratory illness may not possess the necessary sensitivity for early diagnostic suspicion, at least in the prehospital emergency setting. The findings have potential implications for early identification of COVID-19 and effective strategies to mitigate infectious risk during emergency care.

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Article Information

Accepted for Publication: June 4, 2020.

Published: July 8, 2020. doi:10.1001/jamanetworkopen.2020.14549

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

Corresponding Author: Thomas Rea, MD, MPH, Department of Medicine, University of Washington, 401 Fifth Avenue, Suite 1200, Seattle, WA 98104 (

Author Contributions: Ms Barnard and Dr Rea had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Yang, Barnard, Drucker, Counts, Murphy, Sayre, Rea.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Yang, Barnard, Rodriquez, Jacinto, May, Rea.

Critical revision of the manuscript for important intellectual content: Emert, Drucker, Schwarcz, Counts, Murphy, Guan, Kume, Sayre, Rea.

Statistical analysis: Barnard, Emert, Drucker, Counts, May.

Obtained funding: Jacinto.

Administrative, technical, or material support: Yang, Emert, Drucker, Schwarcz, Counts, Murphy, Guan, Kume, Rodriquez, Jacinto, Rea.

Supervision: Yang, Emert, Jacinto, Sayre, Rea.

Conflict of Interest Disclosures: Dr Sayre reported receiving support from Stryker to support fellowship medical education outside the submitted work. No other disclosures were reported.

Additional Contributions: We wish to acknowledge Public Health–Seattle and King County, the Washington State Department of Health, the US Centers for Disease Control and Prevention, and the telecommunicators and emergency medical service professionals of Seattle and greater King County.

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