Predictors of Critical Illness During Different COVID-19 Pandemic Periods Compared With Seasonal Influenza

The study aimed to identify predictors of critical illness in COVID-19 patients over different pandemic periods and compare these with seasonal influenza cases in Sweden. It found that while COVID-19 hospitalization rates were consistently higher than those for influenza, demographic and clinical characteristics converged during later stages of the pandemic, particularly during the Omicron period, which resembled influenza patterns. Key predictors of severe illness included advanced age, male sex, chronic comorbidities, and unvaccinated status for COVID-19.