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Results from a test-and-treat study for influenza among residents of homeless shelters in King County, WA: a stepped-wedge cluster-randomized trial.
  • +12
  • Julia Rogers,
  • Amanda Casto,
  • Gift Nwanne,
  • Amy Link,
  • Miguel Martinez,
  • Callista Nackviseth,
  • Caitlin Wolf,
  • James Hughes,
  • Janet Englund,
  • Nancy Sugg,
  • Timothy M Uyeki,
  • Peter Han,
  • Brian Pfau,
  • Jay Shendure,
  • Helen Chu
Julia Rogers
University of Washington

Corresponding Author:jr66@uw.edu

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Amanda Casto
University of Washington School of Medicine
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Gift Nwanne
Fred Hutchinson Cancer Research Center
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Amy Link
University of Washington
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Miguel Martinez
University of Washington
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Callista Nackviseth
University of Washington
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Caitlin Wolf
University of Washington
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James Hughes
University of Washington
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Janet Englund
Seattle Children's Research Institute
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Nancy Sugg
University of Washington
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Timothy M Uyeki
Centers for Disease Control and Prevention
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Peter Han
Brotman Baty Institute for Precision Medicine
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Brian Pfau
Brotman Baty Institute for Precision Medicine
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Jay Shendure
University of Washington
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Helen Chu
University of Washington
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Abstract

Background Persons experiencing homelessness face increased risk of influenza as overcrowding in congregate shelters can facilitate influenza virus spread. Data regarding on-site influenza testing and antiviral treatment within homeless shelters remains limited. Methods We conducted a cluster-randomized stepped-wedge trial of point-of-care molecular influenza testing coupled with antiviral treatment with baloxavir or oseltamivir in residents of 14 homeless shelters in Seattle, WA, USA. Residents ≥3 months with cough or ≥2 acute respiratory illness (ARI) symptoms and onset <7 days were eligible. In control periods, mid-nasal swabs were tested for influenza by RT-PCR. The intervention period included on-site rapid molecular influenza testing and antiviral treatment for influenza-positives if symptom onset was <48 hours. The primary endpoint was monthly influenza virus infections in the control versus intervention period. Influenza whole genome sequencing was performed to assess transmission and antiviral resistance. Results During 11/15/2019–4/30/2020, and 11/2/2020–4/30/2021, 1,283 ARI encounters from 668 participants were observed. Influenza virus was detected in 51 (4%) specimens using RT-PCR, (A=14; B=37); 21 influenza virus infections were detected from 269 (8%) of intervention-eligible encounters by rapid molecular testing and received antiviral treatment. 37% of ARI-participant encounters reported symptom onset <48 hours. The intervention had no effect on influenza virus transmission (adjusted relative risk 1.73, 95% CI 0.50–6.00). Of 23 influenza genomes, 86% of A(H1N1)pdm09 and 81% of B/Victoria sequences were closely related. Conclusion Our findings suggest feasibility of influenza test-and-treat strategies in shelters. Additional studies would help discern an intervention effect during periods of increased influenza activity
01 Nov 2022Submitted to Influenza and other respiratory viruses
02 Nov 2022Submission Checks Completed
02 Nov 2022Assigned to Editor
24 Nov 2022Editorial Decision: Revise Minor
09 Dec 20221st Revision Received
12 Dec 2022Submission Checks Completed
12 Dec 2022Assigned to Editor
12 Dec 2022Editorial Decision: Accept