Veterans Study Suggested Current JN.1 Strain Not Less Severe
ST. LOUIS — The risk of dying while hospitalized for COVID-19 might have decreased since the pandemic began, but SARS-CoV-2 still has a considerably higher mortality rates than seasonal influenza, according to a new VA study.
“The findings should be interpreted in the context of nearly twice as many hospitalizations for COVID-19 compared with seasonal influenza during 2023-2024,” wrote Ziyad Al-Aly, MD, and colleagues at the VA St Louis Health Care System.
The study team evaluated the risk of death in a cohort of people hospitalized for COVID-19 or seasonal influenza this past fall-winter 2023-2024.
“In the first year of the COVID-19 pandemic, risk of death in people hospitalized for COVID-19 was substantially higher than in people hospitalized for seasonal influenza,” the authors wrote in a research letter published in JAMA. “The risk of death due to COVID-19 has since declined. In fall-winter 2022-2023, people hospitalized for COVID-19 had a 60% higher risk of death compared with those hospitalized for seasonal influenza.”1
The researchers pointed out that new variants of SARS-CoV-2 have continued to appear, including the emergence of JN.1, the predominant variant in the United States since Dec. 24, 2023.
To reach those conclusions, the researchers used VA electronic health records from all 50 states and identified patients who were admitted to the hospital with a diagnosis of COVID-19 or seasonal influenza between Oct. 1, 2023, and March 27, 2024, and within 2 days before and 10 days after a positive test result for SARS-CoV-2 or influenza. The cohort was followed for 30 days, until death or until March 31, 2024.
Excluded were any patients with either infection hospitalized for another reason, or those hospitalized for both COVID-19 and seasonal influenza. 5.70% Death Rate
Ultimately, the study involved 8,625 participants hospitalized for COVID-19 (unadjusted death rate, 5.70% at 30 days) and 2,647 participants hospitalized for seasonal influenza (unadjusted death rate, 3.04% at 30 days).
The results indicated that patients hospitalized for COVID-19 had a higher risk of death compared with those hospitalized for seasonal influenza (adjusted death rate, 5.70% vs. 4.24% at 30 days; adjusted HR, 1.35 [95% CI, 1.10-1.66]). No statistically significant difference in the risk of death among people hospitalized for COVID-19 before and during the JN.1-predominant era (adjusted death rate, 5.46% vs. 5.82% at 30 days; adjusted HR, 1.07 [95% CI, 0.89-1.28]) was identified.
“The study found that in fall-winter 2023-2024, the risk of death in patients hospitalized for COVID-19 was greater than the risk of death in patients hospitalized for seasonal influenza,” Al-Aly and his co-authors advised. “Compared with a study using the same database and methods, the death rate at 30 days was 5.97% in 2022-2023 vs. 5.70% in 2023-2024 for COVID-19 and 3.75% in 2022-2023 vs. 4.24% in 2023-2024 for influenza.”
The report noted that changes in either the SARS-CoV-2 or influenza viruses or in their care, such as the use of vaccines or antivirals, could influence the comparative risk of death each season.
“The results also showed that, at the level of statistical power available in this study, there was no significant difference in risk of death among those hospitalized for COVID-19 before and during the JN.1-predominant era—suggesting that JN.1 may not have a materially different severity profile than the variants that immediately preceded it,” the authors explained.
The study was limited because the VA population, which is older and mostly male, might not represent the general population. In addition, causes of death were not examined.
- Xie Y, Choi T, Al-Aly Z. Mortality in Patients Hospitalized for COVID-19 vs. Influenza in Fall-Winter 2023-2024. JAMA. Published online May 15, 2024. doi:10.1001/jama.2024.7395