According to two US studies from the first year of the COVID-19 pandemic, People hospitalized for the Omicron variant infection had a 5-times higher risk of 30-day mortality than those treated for seasonal influenza. Since then, many things have changed, including the SARS-CoV-2 virus, clinical therapy, population-level immunity, and maybe influenza mortality.
This study examined the mortality risk in the fall and winter of 2022-2023 and found that US veterans hospitalized with Omicron died at a 61% higher rate than hospitalized flu patients, while Israeli people had a 55% lower mortality rate than those admitted for Omicron during the flu season of 2021-2022.
Researchers from The Veteran’s Affairs Saint Louis Health Care System examined death rates among 8,996 veterans hospitalized for COVID-19 and 2,403 for influenza from October 1, 2022, to January 31, 2023, in a research letter that was published yesterday in JAMA. The average age of the patients was 73.
In comparison to 76 of 2,403 (3.16%) flu patients, 538 (5.98%) of the 8,996 COVID-19 patients passed away within 30 days. The 30-day death rate for COVID-19 was 5.97%, and for influenza, it was 3.75%, giving an excess death rate of 2.23%. Admissions for COVID-19 were linked to a greater risk of death than those for the flu.
With more COVID-19 immunizations, the probability of mortality decreased (P=.009 for the interaction between unvaccinated and vaccinated patients; P.001 for the interaction between unvaccinated and boosted patients).
The authors noted that two or three times more people in the United States were hospitalized for COVID-19 than flu during the study period. “However, 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 researchers said, “The risk of death declined with an increasing number of COVID-19 vaccinations.”
The decrease in mortality among hospitalized COVID-19 patients may be attributed to the development of the variation, elevated levels of immunity from vaccination and prior infections, and improved clinical treatment over time.
The COVID vaccine was discovered to be protective, decreasing the risk of death with each additional dose. Variant evolution, elevated immunity from immunization and prior infection, and improved clinical treatment throughout time may be to blame for decreased death rates.
They wrote, “The increased risk of death was greater among unvaccinated individuals compared with those vaccinated or boosted findings that highlight the importance of vaccination in reducing the risk of COVID-19 death.”
Researchers from the Rabin Medical Center at Belinison Hospital in Israel compared the outcomes of 167 hospitalized COVID-19 Omicron patients and 221 patients admitted for the flu in December 2021 and January 2022 in an observational study that will be presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) from April 15 to 18 in Copenhagen, Denmark.
The median age of the patients was 71 and 65 years, respectively. The patients had higher rates of underlying illnesses like diabetes and high blood pressure and required more assistance with daily living tasks. Flu patients were also more likely to have asthma than non-flu patients.
More frequently than flu patients, COVID-19 patients required supplemental oxygen, invasive mechanical ventilation, and vasopressors to increase blood pressure.
Compared to flu patients, the 30-day death rate was 9% as opposed to 26%, a difference of 55%.
The authors wrote, “Omicron was considered a less virulent variant with lower case fatality rates than the original strain, even though hospitalized patients with omicron variant still have a higher mortality rate than in seasonal influenza. This could be due to differences in underlying comorbidities of patients, the pathogenicity of the virus, population immunity, and host responses to infection.”
Lead author Alaa Atamna, MD, said in a news release from the ECCMID that the findings highlight the value of vaccination,
He said, “There is one basic step people can take that may alter the trajectory of either epidemic, get the vaccines for flu and COVID-19, especially if you are older and have underlying illnesses.”
The researcher said, “The double whammy of overlapping influenza and COVID-19 epidemics will increase the complexity of the disease and the burden on health systems. One basic step people can take that may alter the trajectory of either epidemic is getting the vaccines for flu and COVID-19, especially if you are older and have underlying illnesses.”
This research was funded by the US Department of Veterans Affairs.