COVID-19 Resulted in Significantly More Hospitalizations than Influenza

The coronavirus disease 2019 (COVID-19) results in nearly twice as many hospitalizations and 3 times as many deaths than influenza during the peak 2018/2019 flu season in France, according to new data.

A research team based in France found during a two-month period in the spring of 2020 there were 89,530 patients hospitalized with COVID-19, compared to 45,819 patients with the flu in a three-month span the prior year.

Using data from the French national administrative database, the investigators examined details for all patients admitted to either public or private hospitals in France, including information about why they were admitted and the care they receiving during their hospital stay.

The researchers used this data to compare hospital admissions with COVID-19 for March and April in 2020 with seasonal flu hospital admissions between December 2018 and February 2019.

One explanation for the difference in hospitalization could be due to existing immunity to influenza in the population as a result of previous infections or vaccination, while virtually no one had previous immunity to COVID-19.

“Our study is the largest to date to compare the two diseases and confirms that COVID-19 is far more serious than the flu,” Catherine Quantin, from the University hospital of Dijon and from L'Institut National de la Santé et de la Recherche Médicale (Inserm), France, who jointly led the study, said in a statement. “The finding that the COVID-19 death rate was three times higher than for seasonal influenza is particularly striking when reminded that the 2018/2019 flu season had been the worst in the past five years in France in terms of number of deaths.”

Using the same data during the same time periods, the researchers identified 15,104 deaths (16.9%) from COVID-19, compared to 2640 (5.8%) deaths from influenza.

Overall, a greater proportion of patients with COVID-19 experienced a severe illness requiring intensive care than those admitted with influenza (number admitted to ICU: COVID-19, 14,585 [16.3%] vs influenza, 4926 [10.8%]).

In addition, COVID-19 patients were twice as likely to require invasive mechanical ventilation during their hospital stay (number of patients: COVID-19, 8,684 [9.7%] vs influenza, 1,833/45,819 [4.0%]), while the average length of stay for COVID-19 was almost twice as long (mean length of ICU stay: COVID-19, 15 days vs influenza, 8 days).

More than 25% of COVID-19 patients experienced acute respiratory failure, where their lungs were unable to get oxygen into the body. On the other hand, less than 20% of flu patients experienced this (number of patients: COVID-19, 24,317 [27.2%] vs influenza 7977 [17.4%]).

The most common underlying medical conditions among patients admitted to the hospital with COVID-19 were high blood pressure (29,622; 33.1%), being overweight or obese (10,116; 11.3%), and diabetes (17,050; 19.0%).

“Taken together, our findings clearly indicate that COVID-19 is much more serious than seasonal influenza,” Dr Pascale Tubert-Bitter, research director at L'Institut National de la Santé et de la Recherche Médicale (Inserm) and from the University Paris-Saclay, France, who jointly led the study, said in a statement. “At a time when no treatment has been shown to be effective at preventing severe disease in COVID-19 patients, this study highlights the importance of all measures of physical prevention and underlines the importance of effective vaccines.”

On the positive side, only 1227 children (1.4%) were hospitalized with COVID-19, compared to 8942 (19.5%) with influenza. However, among those aged under 5 years, a larger proportion of COVID-19 patients (n = 14; 2.3%) required intensive care support than did those with influenza (n = 65; 0.9%).

The case fatality rate in the COVID-19 group was lower than for influenza (number of deaths COVID-19: 3 [0.5%] vs influenza: 13 [0.2%]).