Common human coronaviruses seem at least as severe as influenza in patients hospitalized with acute respiratory infection: results from 8-year hospital-based surveillance in Quebec, Canada.

BACKGROUND: Few data exist about the role of common human coronaviruses (HCoV) in patients hospitalized for acute respiratory illness (ARI) and the severity of these infections compared to influenza. METHODS: Prospective data on virus etiology of ARI hospitalizations during the peaks of 8 influenza seasons (2011-12 to 2018-19) in Quebec, Canada, was used to compare patients with HCoV to those with influenza infections; generalized estimation equations models were used for multivariate analyses. RESULTS: We identified 340 HCoV infections which affected 11.6%(n=136) of children and 5.2%(n=204) of adults hospitalized with ARI. The majority of children (75%) with HCoV infections were also coinfected with other respiratory viruses compared to 24% of the adults (p<0.0001). No deaths were recorded in children; 5.8% of adults with HCoV monoinfection compared to 4.2% of those with influenza monoinfection died (p=0.226). The risk of pneumonia was non-significantly lower in children with HCoV than with influenza but similarly high in adults. Markers of severity (length-of-stay, intensive-care admissions and case-fatality ratio) were comparable between these infections in multivariate analyses, both in children and adults. CONCLUSIONS: In children and adults hospitalized with ARI, HCoV infections were less frequent than influenza infections, but HCoV monoinfections were as severe as influenza monoinfections.