Changes in hospitalizations and emergency department respiratory viral diagnosis trends before and during the COVID-19 pandemic in Ontario, Canada

Abstract

Introduction Population-level surveillance systems have demonstrated reduced transmission of non-SARS-CoV-2 respiratory viruses during the COVID-19 pandemic. In this study, we examined whether this reduction translated to reduced hospital admissions and emergency department (ED) visits associated with influenza, respiratory syncytial virus (RSV), human metapneumovirus, human parainfluenza virus, adenovirus, rhinovirus/enterovirus, and common cold coronavirus in Ontario. Methods Hospital admissions were identified from the Discharge Abstract Database and exclude elective surgical admissions and non-emergency medical admissions (January 2017-March 2022). Emergency department (ED) visits were identified from the National Ambulatory Care Reporting System. International Classification of Diseases (ICD-10) codes were used to classify hospital visits by virus type (January 2017-May 2022). Results At the onset of the COVID-19 pandemic, hospitalizations for all viruses were reduced to near-trough levels. Hospitalizations and ED visits for influenza (9,127/year and 23,061/year, respectively) were nearly absent throughout the pandemic (two influenza seasons; April 2020-March 2022). Hospitalizations and ED visits for RSV (3,765/year and 736/year, respectively) were absent for the first RSV season during the pandemic, but returned for the 2021/2022 season. This resurgence of hospitalizations for RSV occurred earlier in the season than expected, was more likely among younger infants (age ≤6 months), more likely among older children (aged 6.1–24 months), and less likely to comprise of patients residing in higher areas of ethnic diversity (p<0.0001). Conclusion During the COVID-19 pandemic, there was a reduced the burden of other respiratory infections on patients and hospitals. The epidemiology of respiratory viruses in the 2022/23 season remains to be seen.

Development of a Melting-Curve-Based Multiplex Real-Time PCR Assay for the Simultaneous Detection of Viruses Causing Respiratory Infection

“…However, in simulated swabs saturated with synthetic mucus and spiked with the viruses, amplification signals were detected for all specific genetic markers. This result may be attributed to a reported reduction in positive cases and hospitalizations due to other respiratory viruses during the COVID-19 pandemic, as indicated in previous studies [14][15][16]. Moreover, as mentioned before, these viral agents are common causes of respiratory infections, mainly among children [23].…”

“…Nevertheless, the COVID-19 pandemic has impacted the epidemiology of viral infections, including the genetic diversity of these non-SARS-CoV-2 viral agents during the pandemic. A significant decrease in respiratory infections and hospitalizations caused by non-SARS-CoV-2 viruses has been observed globally [14][15][16]. Despite this decrease, cases of co-infection involving SARS-CoV-2 and these viral agents have also been reported during the COVID-19 pandemic [17][18][19].…”

Increased bronchiolitis burden and severity after the pandemic: a national multicentric study

“…Another remarkable finding is the trend of influenza virus that was never detected in our patients during the containment measures and the following year [ 18 ] but spread during this winter season to reach a higher incidence compared to the pre-pandemic years.…”

SARS-CoV-2 infection among physicians over time in Ontario, Canada: a population-based retrospective cohort study

“…Despite this, information about SARS-CoV-2 positivity among physicians over time and by specialty is lacking, with the majority of studies being limited to the first year of the pandemic (9)(10)(11)(12). Following the first year, changes in masking practices, public space restrictions, return to in-person learning in schools, fatigue among health care workers, and the introduction of more infectious variant strains may have contributed to changing patterns of infection (13)(14)(15). Thus, a more contemporary analysis of trends is needed.…”