CLINICAL QUESTION

What are the comparative mortality rates for adults hospitalized with influenza, COVID-19, or respiratory syncytial virus (RSV) infections?

BOTTOM LINE

Even in adults infected with the milder Omicron variant, mortality was substantially higher in people who presented to the emergency department with COVID-19 than for those with influenza or RSV. (Level of Evidence = 2b)

SYNOPSIS

Although the world has largely returned to normal behavior regarding the prevention of the spread of respiratory infections, COVID-19 continues to be a concerning source of mortality. The researchers identified patients who presented to the emergency department with influenza, COVID-19, or RSV at six Swedish hospitals between 2021 and 2022 and compared them with patients who presented before the pandemic (between 2015 and 2019). In 2021 and 2022, 30-day mortality was 7.9% in 4,833 patients with the Omicron variant of COVID-19, 2.5% in 1,099 patients with influenza, and 6.0% in 453 patients with RSV. After adjusting for differences between groups, mortality was higher for COVID-19 than for influenza (adjusted odds ratio [aOR] = 2.36; 95% CI, 1.60 to 3.62) or RSV (aOR = 1.42; 95% CI, 0.94 to 2.21). The increased mortality compared with influenza was higher for people who were not vaccinated against COVID-19 than for those who were vaccinated (aOR = 5.51 vs. 2.0). The comparisons were similar for patients with influenza or RSV before and during the pandemic.

Study design: Cohort (retrospective)

Funding source: Government

Setting: Emergency department

Reference: Hedberg P, Karlsson Valik J, Abdel-Halim L, et al. Outcomes of SARS-CoV-2 Omicron variant infections compared with seasonal influenza and respiratory syncytial virus infections in adults attending the emergency department: a multicenter cohort study. Clin Infect Dis. 2024;78(4):900-907.

Editor’s Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.