Adults hospitalised with the Omicron variant have a higher death rate than those hospitalised with seasonal influenza, even though Omicron is considered less virulent with lower case fatality rates than the Delta and Alpha strains, new research has revealed.
The study by Dr Alaa Atamna and colleagues from the Rabin Medical Center at Belinison Hospital in Israel found that adults (18 years or older) hospitalised with influenza were 55 per cent less likely to die within 30 days than those hospitalised with Omicron during the 2021-2022 influenza season.
Influenza and Covid-19 are both respiratory diseases with similar modes of transmission.
To find out more, researchers compared the clinical outcomes of patients hospitalised with Covid-19 (Omicron variant) and those hospitalised with influenza at a large academic hospital in Israel.
Overall, 63 patients died within 30 days — 19 admitted with influenza and 44 hospitalised with Omicron.
Patients with Omicron tended to have higher overall comorbidity scores, needed more assistance performing activities of daily living (washing and dressing), and were more likely to have high blood pressure and diabetes, whereas asthma was more common in those hospitalised with influenza.
Respiratory complications and need for oxygen support and mechanical ventilation were also more common in Omicron cases than in seasonal influenza.
“A possible reason for the higher Omicron death rate is that patients admitted with Omicron were older with additional major underlying illnesses such as diabetes and chronic kidney disease,” said Dr Atamna.
The difference might also be due to an exaggerated immune response in Covid-19, and that vaccination against Covid-19 was far lower among patients with Omicron,” he added.
The double whammy of overlapping influenza and Covid-19 epidemics will increase the complexity of disease and the burden on health systems, said the study to be presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Copenhagen this month.
