(Bloomberg) -- Covid-19 remained a bigger killer than the flu last winter, despite hopes the pandemic virus would eventually blend into the background with other respiratory germs that cause seasonal epidemics, a US study showed.

Patients hospitalized for Covid had a 35% higher risk of dying within 30 days than influenza patients, Ziyad Al-Aly and colleagues at the clinical epidemiology center of the Veterans Affairs St Louis Health Care System in Missouri found. Covid posed a 60% higher mortality risk than flu in hospitalized patients during the 2022-2023 season, the same researchers showed last year.

The findings, published Wednesday in JAMA, should be interpreted in the context of nearly twice as many hospitalizations for Covid compared with seasonal flu from October 2023 to March 2024, they said. 

Although the death rate among Covid patients declined to 5.7% in that period from 6% a year earlier, the study indicates that Covid’s propensity to cause more damage outside the lungs still makes it a more dangerous pathogen, even as immunity to the virus builds.

“We did the 2024 Covid-versus-flu rematch thinking that we may find that risk of death in Covid may have sufficiently declined to become equal with the risk of death from flu,” Al-Aly told Bloomberg. “But the reality remains that Covid carries a higher risk of death than the flu.”

The findings were based on an analysis of electronic health records from US veterans across all 50 states. Although most VA users are older, white males, the data included hundreds of female and non-white patients. Patients with either Covid or flu hospitalized for another reason — or those hospitalized for both illnesses — were excluded from the study.

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Among Covid patients, there was no significant difference in the risk of dying before and during the period in which JN.1 predominated around Christmas 2023, suggesting that the omicron subvariant may not have a materially different severity profile than those that immediately preceded it, the researchers said.

“Overall, I think this means that we still need to take Covid seriously,” Al-Aly said. “Trivializing it as an inconsequential ‘cold,’ as we often hear, doesn’t mesh or align with reality.”

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