COVID-19 remained deadlier than flu this past season
Key takeaways:
- Being hospitalized for COVID-19 vs. seasonal influenza was associated with an increased risk for death.
- Risk for death was greater among unvaccinated people compared with patients who were vaccinated or boosted.
COVID-19 remained deadlier than influenza this past season, although the difference in mortality shrunk compared with past years, according to a study comparing outcomes of patients hospitalized with the illnesses.
“In the first year of the COVID-19 pandemic, two U.S. studies suggested that people hospitalized for COVID-19 had nearly five times the risk of 30-day mortality compared with those hospitalized for seasonal influenza,” Yan Xie, PhD, senior clinical epidemiologist at the Saint Louis VA Health Care System’s Clinical Epidemiology Center, and colleagues wrote.
“Since then, much has changed, including SARS-CoV-2 itself, clinical care, and population-level immunity; mortality from influenza may have also changed,” Xie said and colleagues wrote.
Because of this, the researchers sought to determine if COVID-19 was still associated with a higher risk for death compared with seasonal influenza during the fall and winter of 2022-2023.
According to the study, the researchers used patient data from the U.S. Department of Veterans Affairs electronic health databases to assess patients with at least one hospital admission between 2 and 10 days after a positive SARS-CoV-2 or influenza test and admission diagnosis for COVID-19 or influenza between Oct. 1, 2022, and Jan. 31, 2023. All patients were followed until death or through March 2, 2023.
In total, there were 8,996 hospitalizations for COVID-19 and 2,403 hospitalizations for seasonal influenza. They researchers determined that hospitalization for COVID-19 was associated with a higher risk for death (HR = 1.61; 95% CI, 1.29-2.02) compared with hospitalizations for influenza. They added that the mortality rate at 30 days was 5.97% for COVID-19 and 3.75% for influenza, with an excess death rate of 2.23% (95% CI, 1.32%-3.13%).
The authors wrote that this finding “should be interpreted in the context of a two to three times greater number of people being hospitalized for COVID-19 vs. influenza in the U.S. during the assessed timeframe.”
Additionally, the study showed that the overall risk for death decreases as vaccinations increased (P = .009 for interaction between unvaccinated and vaccinated; P < .001 for interaction between unvaccinated and boosted), which the authors said further highlights the importance of vaccination.
“The difference in mortality rates between COVID-19 and influenza appears to have decreased since early in the pandemic; death rates among people hospitalized for COVID-19 were 17% to 21% in 2020 vs. 6% in this study, while death rates for those hospitalized for influenza were 3.8% in 2020 vs. 3.7% in this study,” the authors wrote. “The decline in death rates among people hospitalized for COVID-19 may be due to changes in SARS-CoV-2 variants, increased immunity levels (from vaccination and prior infection) and improved clinical care.”
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