Just a bad flu? Tackling the “infodemic” in Ireland through a comparative analysis of hospitalised cases of COVID-19 and influenza

Beatty, Kenneth; Hamilton, Vida; Kavanagh, Paul M.

Objectives COVID-19 infection has been compared to seasonal influenza as an argument against non-pharmacological population based infection control measures known as “lockdowns”. Our study sought to compare disease severity measures for patients in Ireland hospitalised with COVID-19 against those hospitalised with seasonal influenza. Study Design Retrospective population-based cohort study. Methods COVID-19 hospital episodes and seasonal influenza hospital episodes were identified using relevant International Classification of Disease (ICD-10) codes in the Irish national hospitalisation dataset. Occurrence of key metrics of disease severity, length of stay, intensive care admission, ventilatory support, haemodialysis and in-hospital mortality were measured and compared between the two groups using odds ratios with 95% confidence intervals, stratified by age. Results Hospitalised COVID-19 episodes had a mean length of stay more than twice as long as hospitalised influenza episodes (17.7 days vs. 8.3 days). The likelihood of all measures of disease severity were greater in COVID-19 episodes, and the odds of in-hospital mortality were five-fold higher in this group compared with seasonal influenza episodes (OR 5.07, 95% C.I. 4.29-5.99, p<0.001). Greater likelihood of increased disease severity was observed for COVID-19 episodes in most age groups. Conclusions COVID-19 is a more severe illness than seasonal influenza in hospitalised cohorts. It is imperative that public health professionals ensure evidence-based advocacy is part of the response to COVID-19 to tackle a dangerous “infodemic” which can undermine public health control measures.