Elsevier

Mayo Clinic Proceedings

Volume 96, Issue 12, December 2021, Pages 3042-3052
Mayo Clinic Proceedings

Original article
Decline of Influenza and Respiratory Viruses With COVID-19 Public Health Measures: Alberta, Canada

https://doi.org/10.1016/j.mayocp.2021.09.004Get rights and content
Under a Creative Commons license
open access

Abstract

Objective

To determine the incidence of influenza and noninfluenza respiratory viruses (NIRVs) pre-/post-implementation of public health measures aimed to decrease coronavirus disease 2019 (COVID-19) transmission using population-based surveillance data. We hypothesized that such measures could reduce the burden of respiratory viruses (RVs) transmitting via the same routes.

Patients and Methods

An interrupted time-series analysis of RV surveillance data in Alberta, Canada, from May 2017 to July 2020 was conducted. The burden of influenza and NIRVs before and after intervention initiation at week 11 was compared. The analysis was adjusted for seasonality, overdispersion, and autocorrelation.

Results

During the study period, an average of 708 and 4056 weekly respiratory multiplex molecular panels were conducted pre-/post-intervention, respectively. We found significant reductions in test positivity rates in the postintervention period for influenza (-94.3%; 95% CI, -93.8 to 97.4%; P<.001) and all NIRVs (-76.5%; 95% CI, -77.3 to -75.8%; P<.001) in the crude model, and -86.2% (95% CI, -91.5 to -77.4%: P<.001) and -75% (95% CI, -79.7 to -69.3%; P<.001), respectively, in the adjusted models. Subanalyses for individual viruses showed significant decreases in respiratory syncytial virus, human metapneumovirus, enterovirus/rhinovirus, and parainfluenza. For non–severe acute respiratory coronavirus 2 human coronaviruses, the decline was not statistically significant after adjustment (-22.3%; 95% CI, -49.3 to +19%, P=.246).

Conclusion

The implementation of COVID-19 public health measures likely resulted in reduced transmission of common RVs. Although drastic lockdowns are unlikely to be required given widespread COVID-19 vaccination, targeted implementation of such measures can lower RV disease burden. Studies to evaluate relative contributions of individual interventions are warranted.

Abbreviations and Acronyms

hCoV
human coronavirus
hERV
human entero/rhinovirus
hMPV
human metapneumovirus
IRR
incident rate ratio
ITS
interrupted time series
NIRV
noninfluenza respiratory virus
PCR
polymerase chain reaction
PIV
parainfluenza virus
RSV
respiratory syncytial virus
TPR
test positivity rate

Cited by (0)

Dr. Jamil N Kanji is now with the Division of Infectious Diseases, Department of Medicine Cumming School of Medicine and Department of Pathology & Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Public Health Laboratory, Alberta Precision Laboratories, Calgary, Alberta, Canada.

Dr. Nelson Lee is now with the Division of Clinical Public Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.

Potential Competing Interests: Dr Lee reports nonfinancial support from Shionogi Ltd; personal fees and nonfinancial support from Janssen Pharmaceuticals and F. Hoffmann-La Roche, Sanofi Pasteur; personal fees and other from Gilead Sciences Ltd, Genetech Inc, Seqirus Inc, and Genetech Inc; and personal fees from hVIVO Ltd, Gilead Sciences Ltd, and CIDARA Ltd. Dr Doroshenko reported receiving personal fees from Sanofi Pasteur for an advisory role and research grants paid to the University of Alberta from Canadian Institutes of Health Research, Public Health Agency of Canada, Alberta Health, and University of Alberta Hospital Foundation outside the submitted work. The remaining authors report no potential competing interests.