The changing landscape of respiratory viruses contributing to respiratory hospitalizations: results from a hospital-based surveillance in Quebec, Canada, 2012-13 to 2021-22 (Preprint)

Abstract

A comprehensive description of the combined effect of SARS-CoV-2 and respiratory viruses (RV) other than SARS-CoV-2 (ORV) on hospitalizations is lacking.

We compared viral etiology of acute respiratory infections (ARI) hospitalizations before and during two pandemic years from a surveillance network in Quebec, Canada.

We compared detection of ORV and SARS-CoV-2 during 2020-21 and 2021-22 to 8 pre-pandemic influenza seasons in patients hospitalized with ARI who were tested systematically by a multiplex PCR.

During pre-pandemic influenza seasons, overall RV detection was 92.7% (1,493) (48.3% respiratory syncytial virus (RSV)) in children and 62.8% (4,339) (40.1% influenza) in adults. Overall RV detection in 2020-21 was 58.6% (29) in children (all ORV) and 43.7% (333) in adults (3.4% ORV, 40.3% SARS-CoV2, both including coinfections). In 2021-22 overall RV detection was 91.0% (201) in children (82.8% ORV, 8.1% SARS-CoV-2, both including coinfections) and 55.5% (527) in adults (14.1% ORV, 41.4% SARS-CoV-2, both including coinfections). Virtually no influenza was detected in 2020-21 and in 2021-22 up to epi-week 2022-9 presented here; no RSV was detected in 2020-21. In 2021-22, detection of RSV was comparable to pre-pandemic years but with an unusually early season. There were significant differences in ORV and SARS-CoV-2 detection between time periods and age groups.

Significant continuous shifts in age distribution and viral etiology of ARI hospitalizations occurred during two pandemic years. This reflects evolving RV epidemiology and underscores the need for increased scrutiny of ARI hospitalization etiology to inform tailored public health recommendations.