Risk for Acquiring COVID-19 Illness Among Emergency Medical Service Personnel Exposed to Aerosol-Generating Procedures

Aubrey Brown; Leilani Schwarcz; Catherine R. Counts; Leslie M. Barnard; Betty Y. Yang; Jamie M. Emert; Andrew Latimer; Christopher Drucker; John Lynch; Peter J. Kudenchuk; Michael R. Sayre; Thomas Rea


Emerging Infectious Diseases. 2021;27(9):2340-2348. 

In This Article

Abstract and Introduction


We investigated the risk of coronavirus disease (COVID-19) patients transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to emergency medical service (EMS) providers, stratified by aerosol-generating procedures (AGP), in King County, Washington, USA, during February 16–July 31, 2020. We conducted a retrospective cohort investigation using a statewide COVID-19 registry and identified 1,115 encounters, 182 with ≥1 AGP. Overall, COVID-19 incidence among EMS personnel was 0.57 infections/10,000 person-days. Incidence per 10,000 person-days did not differ whether or not infection was attributed to a COVID-19 patient encounter (0.28 vs. 0.59; p>0.05). The 1 case attributed to a COVID-19 patient encounter occurred within an at-risk period and involved an AGP. We observed a very low risk for COVID-19 infection attributable to patient encounters among EMS first responders, supporting clinical strategies that maintain established practices for treating patients in emergency conditions.


Dynamic circumstances, time sensitivity, limited information about widely variable scenes encountered, and heterogeneous patient characteristics make emergency medical service (EMS) responses inherently challenging. The global coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has now forced EMS providers to also consider how best to manage their own potential exposure, particularly when a patient's infection status is unknown.[1,2]

During outbreaks of severe acute respiratory syndrome in 2003 and Middle East respiratory syndrome in 2012, many healthcare workers became infected while caring for patients.[3–5] There is an evolving understanding of the risk of patients transmitting COVID-19 to healthcare workers, but less is known about transmitting it to emergency medical first responders or about the specific etiology of infection.[6–10]

Respiratory exposure is the primary mode of COVID-19 transmission.[11,12] Clinical guidelines have evolved to mitigate risk for transmission, especially through aerosolizing procedures used for cardiopulmonary resuscitation (CPR) or airway management. A better understanding of the risks related to patient care itself could further inform clinical practice approaches, therapeutic choices, and personal protective equipment (PPE) strategies in an effort to balance risks and benefits for providers and patients while striving to maintain best practices for patient care.[4,12,13] Therefore, we investigated the risk for COVID-19 transmission from patient to provider and how use of aerosol-generating procedures (AGP) during the encounter might affect risk levels.