Acute Respiratory Failure and Ventilatory Support in Hospitalized Adults with Viral Respiratory Infection: A Retrospective Cohort Study

Objectives This retrospective cohort study compares the risk and severity of acute respiratory failure (ARF) among adults hospitalized with different respiratory viruses. Materials and methods We included 4,927 adults admitted to Akershus University Hospital, Norway, from 2012–2021 with PCR-confirmed viral infection with influenza A/B, respiratory syncytial virus (RSV), parainfluenza virus (PIV), human metapneumovirus (hMPV), or SARS-CoV-2. ARF was defined as the use of high-flow oxygen, NIV or mechanical ventilation during admission. Logistic regression models estimated adjusted probabilities of respiratory failure and ventilatory support, using influenza A/B as the reference, and adjusted for age, sex, NEWS2, weighted Charlson Comorbidity Index, and other covariates. Results Overall, 11.8% (n=583) met criteria for ARF. Compared with influenza A/B, all other virus groups except hMPV were associated with a higher adjusted probability of ARF. SARS-CoV-2 showed the highest risk, followed by PIV and RSV (all p < 0.01). A similar pattern was seen for non-invasive or mechanical ventilation. Sensitivity analyses using alternative comorbidity adjustments or analyzing patients before and after the COVID-19 pandemic separately produced consistent relative rankings across virus groups. Conclusion SARS-CoV-2, PIV and RSV were associated with increased risk of ARF in hospitalized adults compared with influenza A/B. SARS-CoV-2 strains circulating during the early pandemic showing the greatest risk, while RSV and PIV also conferred a substantial ARF excess risk. These findings underscore the need for clinical vigilance and preventive strategies in patients admitted with viral respiratory tract infections.