COVID is still deadlier than the flu - but the difference is narrowing

Patients hospitalized with COVID-19 were more likely to die than those hospitalized with the flu during the fall and winter of 2023-2024, according to an analysis of VA data.

Among the more than 11,000 patients hospitalized for one of these illnesses last fall and winter, 5.7% of patients with COVID-19 died within 30 days after hospitalization, compared with 4.24% of influenza patients, reported Ziyad Al-Ali, MD, of the St. Louis VA Medical Center, and colleagues.

After adjusting for variables, the risk of death in people hospitalized with COVID-19 was 35% higher (adjusted HR 1.35; 95% CI 1.10–1.66), the authors detail in a letter to JAMA magazine.

Al-Ali said his team was actually surprised by the results. “We basically accepted the public narrative and drank the Kool-Aid like everyone else, thinking that COVID was no longer [more dangerous than the flu], even though... There was no data,” he said. "But the verdict is now clear because we've analyzed the data for the 2023-2024 COVID season, and clearly COVID still has a higher mortality rate than the flu."

Additionally, the authors indicated that the study's findings should be considered in light of the fact that the number of hospitalizations due to COVID-19 was almost double that due to flu season 2023-2024, according to the CDC monitoring service. In the study population, nearly three times more people were hospitalized due to COVID-19 than due to influenza.

However, the results showed that the risk of death in patients hospitalized with COVID-19 decreased compared to the previous 2022-2023 season. In their 2023 study, using the same database and methods, Al-Ali's team found that in the fall and winter of 2022–2023, COVID was about 60% deadlier than influenza in patients hospitalized for these illnesses.

“We must continue to take COVID seriously,” Al-Ali stressed. "I know we're all tired of this pandemic and we're all suffering from pandemic fatigue, but COVID is still a bigger health threat than the flu."

Reassuringly, there was no significant difference in the risk of death among patients hospitalized with COVID-19 before and during the emergence of the JN.1 variant of the SARS-CoV-2 virus (adjusted HR 1.07; 95 %CI 0.89–1.28), indicating that JN.1 is likely no more severe than other recent variants, they suggested. The JN.1 variant became predominant starting at the end of December 2023.

The study analyzed data from VA electronic health records for all 50 states. The researchers identified people hospitalized with a diagnosis of COVID-19 or influenza from October 1, 2023 to March 27, 2024, and who tested positive 2 days before or within 10 days of hospitalization. Patients with any of these conditions who were hospitalized for another reason were excluded. The study cohort included 8,625 participants hospitalized due to COVID-19 and 2,647 participants hospitalized due to seasonal influenza.

After propensity score weighting, the average age of the two cohorts was about 74 years, and 95% were men. About 19% were African American and 65% were white. About 47% were infected before the emergence of the JN.1 variant. Additionally, of patients hospitalized with COVID-19, about 65% have received three or more COVID-19 vaccinations, but approximately 15% have not received any vaccinations. Approximately 44% of the study population had been vaccinated against influenza.

Only about 5.3% of people with COVID-19 have received outpatient antiviral treatment such as nirmatrelvir-ritonavir (Paxlovid), molnupiravir (Lagevrio), or remdesivir (Veklury). In contrast, 8% of patients hospitalized with influenza received outpatient oseltamivir (Tamiflu).

The authors noted that the VA study population was older and primarily male, so the results may not be generalizable to other populations. In addition, the causes of death were not studied.