In a recent publication in the Journal of the American Medical Association Network, researchers sought to determine if COVID-19 remained correlated with a greater risk of death compared with seasonal influenza in the fall-winter season for 2022-2023.

The researchers employed Cox survival models weighted with inverse probability to compare the mortality risk between patients with influenza or COVID-19 who were also hospitalized.

The researchers utilized the U.S. Department of Veterans Affairs (VA) electronic health databases. Between October 1, 2022, and January 31, 2023, the researchers enrolled all individuals with at least one hospital admission record between 2 days before and 10 days after a positive test result for SARS-CoV-2 or influenza and an admission diagnosis for COVID-19 or seasonal influenza. The researchers eliminated 143 participants who were hospitalized with both infections, and the cohort was followed up until the first incident of death, 30 days after hospital admission, or March 2, 2023.

The results revealed that among this patient population, the mortality rates for COVID-19 continue to be higher than those with influenza infections. There were 8,996 hospitalizations, with 538 deaths within 30 days of COVID-19 infections. With regard to seasonal influenza infections, there were 2,403 hospitalizations and 76 deaths.

At 30 days, the mortality rates were reported as 5.97% for COVID-19 and 3.75% for influenza, with an excess death rate of 2.23%. Compared with hospitalization for influenza, hospitalization for COVID-19 was associated with a higher risk of death (hazard ratio, 1.61; 95% CI, 1.29-2.02).

Findings from the subgroup analysis revealed that COVID-19 vaccination was associated with a decreased mortality rate; however, the other factors in the subgroup analysis, such as age and antiviral treatment in the outpatient setting, did not influence the mortality rates.

The authors also indicated that while COVID-19 mortality rates continued to surpass mortality rates associated with influenza, the mortality rates for severe SARS-CoV-2 infections necessitating hospitalization had declined considerably since 2020. In 2020, the reported mortality rates ranged from 17% to 21%. They also noted that seasonal influenza mortality rates have remained stable, with rates of 3.8% and 3.7% in 2020 and 2023, respectively.

The authors wrote, “This study found that, in a VA population in fall-winter 2022-2023, being hospitalized for COVID-19 vs. seasonal influenza was associated with an increased risk of death. This finding should be interpreted in the context of a 2 to 3 times greater number of people being hospitalized for COVID-19 vs. influenza in the U.S. in this period.”

The authors also noted that the heightened mortality risk was more significant among unvaccinated individuals compared with those vaccinated or boosted, and these findings emphasize the magnitude of vaccination in decreasing mortality due to COVID-19 infection.

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