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Community respiratory viral metrics to inform masking in healthcare settings: A regional consensus approach

Published online by Cambridge University Press:  12 February 2024

Eric J. Chow*
Affiliation:
Public Health–Seattle & King County, Seattle, Washington Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington Department of Epidemiology, University of Washington, Seattle, Washington
Lawrence Lee
Affiliation:
Public Health–Seattle & King County, Seattle, Washington
Jennifer Lenahan
Affiliation:
Public Health–Seattle & King County, Seattle, Washington
Sargis Pogosjans
Affiliation:
Public Health–Seattle & King County, Seattle, Washington
Christopher Baliga
Affiliation:
Section of Infectious Diseases, Virginia Mason Medical Center, Seattle, Washington
Mary Fairchok
Affiliation:
Pediatric Infectious Diseases, Mary Bridge Children’s Hospital, Multicare Health System, Tacoma, Washington
John B. Lynch
Affiliation:
Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
John Pauk
Affiliation:
Infectious Disease, Swedish-Providence Health Services, Seattle, Washington
Francis X. Riedo
Affiliation:
EvergreenHealth, Kirkland, Washington
Paul Thottingal
Affiliation:
Communicable Diseases and Organizational Preparedness, Kaiser Permanente Washington, Seattle, Washington
Danielle M. Zerr
Affiliation:
Division of Infectious Diseases, Seattle Children’s Hospital, Seattle, Washington Department of Pediatrics, University of Washington, Seattle, Washington
Nigel Turner
Affiliation:
Tacoma-Pierce County Health Department, Tacoma, Washington
James Lewis
Affiliation:
Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington Snohomish County Health Department, Everett, Washington
Vicki Sakata
Affiliation:
Department of Pediatrics, University of Washington, Seattle, Washington Northwest Healthcare Response Network, Tukwila, Washington
Jeffrey S. Duchin
Affiliation:
Public Health–Seattle & King County, Seattle, Washington Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
*
Corresponding author: Eric J. Chow; Email: erchow@kingcounty.gov
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Abstract

Type
Letter to the Editor
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of The Society for Healthcare Epidemiology of America

To the Editor—Coronavirus disease 2019 (COVID-19) has focused our attention on the immediate and long-term health complications of respiratory viral infections. Public health strategies now must contend with evolving severe acute respiratory coronavirus virus 2 (SARS-CoV-2) community circulation in addition to the morbidity and mortality posed by endemic respiratory viral infections. During the 2022–2023 season, seasonal influenza, and respiratory syncytial virus (RSV) epidemics combined with the ongoing burden of SARS-CoV-2 infections made clear the challenges communities and healthcare systems face moving forward as well as the need to implement comprehensive respiratory virus strategies to protect people who are most vulnerable to complications. Using face masks, and the policies supporting their use, continue to play a key role in current healthcare practices to prevent nosocomial respiratory viral infections.

The use of face masks has reduced transmission of SARS-CoV-2 and other respiratory viral pathogens. Reference Cash-Goldwasser, Reingold, Luby, Jackson and Frieden1 In healthcare settings, universal masking policies decreased risk of healthcare-associated respiratory viral infections as part of a multilayered approach, Reference Wee, Venkatachalam and Sim2 safeguarding the health of patients and healthcare workforce. Severe COVID-19 outcomes continue to occur among vulnerable patients and healthcare facilities face ongoing workforce shortages. Masking policies remain important in preventing infections, especially when the community respiratory viral burden increases. Reference Chow, Lynch and Zerr3 Acknowledging the importance of masking policies, the Northwest Healthcare Response Network, a regional healthcare coalition, in collaboration with public health agencies, convened a face-mask work group of healthcare facilities in Snohomish, King and Pierce County, the 3 most populous Washington counties. We developed a regional consensus policy for universal use of face masks in health care based on emergency department (ED) visits for COVID-19, influenza, and RSV 4 responsible for substantial annual respiratory viral disease burden. Although different policy approaches could be considered, Reference Chow, Lynch and Zerr3 the use of local community burden measures to determine when universal use of face masks in health care would be required for patient care areas allows healthcare facilities to justify and communicate these policies based on local disease activity and transmission risk.

When considering community measures, data should be timely, provide guidance ahead of increased community infections and be simple to message to stakeholders as the basis for why and when universal face-mask requirements would be implemented. Data sources that were regionally available were prioritized. Our public health agencies evaluated the use of syndromic surveillance ED data as a possible measure. In Washington state, syndromic surveillance is conducted through the Rapid Health Information Network (RHINO) 5 and the Centers for Disease Control and Prevention’s National Syndromic Surveillance Program (CDC NSSP). All nonfederal Washington State EDs are required to report healthcare visit data into this system. These data include standardized pathogen discharge diagnosis codes 6 that can be tracked for trends driven by infections in the community. ED discharge diagnoses (ED visits) for COVID-19, influenza, and RSV showed comparable timing to community burden trends reflected by laboratory test reporting 7 before and during the COVID-19 pandemic and thus could serve as an early indicator of respiratory viral activity.

We calculated alert thresholds for each virus using the moving epidemic method (MEM) to indicate the period when universal masking would be implemented. Reference Vega, Lozano and Meerhoff8 The MEM is a validated mathematical approach endorsed by the World Health Organization in their global epidemiological surveillance standards for influenza 9 using epidemic trends from prior seasons. The MEM calculates a point that differentiates periods of lower community viral circulation from time points of increased activity (Fig. 1).

Figure 1. Emergency department visit trends and threshold alerts for COVID-19, influenza and respiratory syncytial virus, King County, Washington. Boxes represent 1 week.

The work group established criteria using community respiratory viral activity published weekly by regional local public health departments to prompt activation of universal use of face masks in patient care areas. In addition to ED visit trends for COVID-19, influenza and RSV, the CDC COVID-19 hospital admission levels were also included as a criterion for activation of universal use of face masks in patient care areas. 4 Although COVID-19 hospitalizations are likely a lagging indicator relative to ED visit trends, they were added to ensure consistency with the CDC recommendations for universal source control. 10 Face masks are required by the time at least 1 pathogen reaches or exceeds the ED visit transmission alert threshold or if CDC COVID-19 hospital admission levels reached or exceeded 10 new COVID-19 hospital admissions per 100,000 population (7-day total) by county (“medium”), whichever occurs first. Healthcare organizations have the flexibility to use other criteria to inform the need for universal use of face masks in facilities earlier than what the established criteria would indicate, including facility-level trends in percent positivity from internal laboratory reports, COVID-19 patient census, healthcare facility outbreak activity, limitations in healthcare facility staffing capacity, or other healthcare facility metrics. The policy calls for universal use of face masks to continue until ED visit trends are below the transmission alert thresholds for all 3 pathogens and CDC COVID-19 hospital admission levels are below “medium” for at least 2 consecutive weeks.

Our approach demonstrates how face-mask policies could be implemented based on readily available local data. The ubiquity of syndromic surveillance allows the use of ED visit data for healthcare facilities seeking to adopt a similar face-mask strategy, although regional variation in data, including differences in health behavior, healthcare access, demographics, and epidemiology, may require local modifications. In our region, some healthcare facilities from counties with fewer ED facilities have referred to data from a neighboring county. We also acknowledge the novel application of MEM to SARS-CoV-2, and this methodology will require reassessment over time. This research highlights the importance of ongoing surveillance and epidemiological capacity in local public health agencies and integrated disease control strategies through partnerships with healthcare systems. Ongoing research will evaluate these metrics and refine optimal thresholds for action. Our regional face-masking consensus models how local public health and healthcare systems can work together to nimbly address a quickly evolving public health challenge.

Acknowledgments

The regional consensus statement would not have been possible without the support of a number of local and state colleagues. We acknowledge the contributions of our epidemiology team including Hollianne Bruce, MPH (Snohomish County Health Department) and Matt George, DVM, MPH (Tacoma–Pierce County Health Department), and our communications team including Sharon Bogan, MPH (Public Health–Seattle & King County), Kari Bray (Snohomish County Health Department and Kenny Via (Tacoma–Pierce County Health Department), and Sara Chronister, MPH (Washington State Department of Health).

Financial support

No financial support was provided relevant to this article.

Competing interests

E.J.C. reports receiving a travel grant from IDSA to attend ID Week 2022 and honoraria from Providence Re.gional Medical Center Everett for presentations on COVID-19. D.M.Z. receives research funding from Merck and consults with Allovir on an endpoint adjudication committee for 2 trials. F.X.R. receives research funding from Pfizer and serves on the speaker’s bureau for GlaxoSmithKline. All other authors report no conflicts of interest relevant to this article.

References

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Wee, LE, Venkatachalam, I, Sim, XYJ, et al. Containment of COVID-19 and reduction in healthcare-associated respiratory viral infections through a multitiered infection control strategy. Infect Dis Health 2021;26:123131.CrossRefGoogle ScholarPubMed
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Figure 0

Figure 1. Emergency department visit trends and threshold alerts for COVID-19, influenza and respiratory syncytial virus, King County, Washington. Boxes represent 1 week.