Nearly twice as many people with covid-19 were hospitalized at the height of the pandemic than with influenza at the height of the 2018/2019 season and the death rate was three times higher, according to a study published in the Lancet Journal.
The study, based on French national data of 89,530 patients hospitalized with covid-19 during the months of March and April of this year and 45,819 patients hospitalized for seasonal influenza between December 2018 and February 28, 2019, shows that the percentage of patients with covid-19 needed intensive care (16.3%) than in the case of influenza (10.8%).
The death rate in hospitalized patients with covid-19 was three times higher (16.9%) than with seasonal influenza (5.8%) and the average stay in intensive care units in the case of covid-19 was almost twice as long (15 days in the covid and eight in the flu).
In contrast, fewer young people under 18 were hospitalized with covid-19 compared with seasonal influenza (1.4% for covid and 19.5% for influenza), but a greater proportion of children under five he needed intensive care for illness caused by the new coronavirus (2.3%) than for flu (0.9%).
According to data published today in The Lancet Respiratory Medicine, the case fatality rate in children under five was similar for the two groups (0.5% in covid-19 and 0.2% in influenza) .
In patients aged 11 to 17 years, the death rate (1.1%) was found to be 10 times higher in those admitted with covid-19 compared to those hospitalized with influenza (0.1%), however, the authors caution that the numbers in this group are too small to draw meaningful conclusions.
The authors indicate that the difference in the hospitalization rate may be in part due to the existing immunity to influenza in the population, whether following a previous infection or a vaccination. In contrast, covid-19 is caused by a new virus to which very few people are expected to have previous immunity.
However, they stress that their findings reinforce the importance of measures to prevent the spread of the two diseases and “are particularly relevant, as several countries prepare for the covid-19 pandemic to overcome seasonal influenza outbreaks.”
Catherine Quantin, from Dijon University Hospital and the National Institute for Health and Medical Research (Inserm), who participated in the study, said: “Our study is the most important to date to compare the two diseases and confirms that Covid-19 is much more serious than the flu ”.
“The finding that the death rate from covid-19 was three times that of seasonal flu is particularly impressive when you remember that the 2018/2019 flu season was the worst in the last five years in France in terms of numbers deaths, ”he added.
The study is based on information from the French national administrative database (Program de Médicalisation des Systèmes d’Information, PMSI). This database includes details of all patients admitted to public or private hospitals in France, including information on the reasons for their admission and the care they received during hospitalization.
In this analysis, the researchers concluded that, overall, the illness was more severe in patients with covid-19 than in those who had been infected with the seasonal influenza virus.
Patients with covid-19 were twice as likely as patients with influenza to require invasive mechanical ventilation during inpatient treatment (9.7% to 4%).
According to the survey, more than one in four patients (27.2%) with covid-19 experienced acute respiratory failure, in which the lungs cannot supply the body with oxygen, compared to less than one patient in five suffer from the flu. (17.4%).
According to data analyzed by researchers, the most common underlying medical conditions in patients admitted with covid-19 were high blood pressure (33.1%), overweight or obesity (11.3%) and diabetes (19.0%).
Pascale Tubert-Bitter, research director at the National Institute of Health and Medical Research (Inserm) and at the University of Paris-Saclay in France, underlined: “At a time when no treatment has taken place. Proven effective in preventing serious illness in patients with covid-19, this study highlights the importance of all effective vaccines”.
However, the researchers pointed out some limitations of their study, namely the fact that flu screening practices varied from hospital to hospital, while the covid-19 test will have been more standardized. Furthermore, it is not possible to say whether the 2018/2019 influenza season is representative of the whole of the seasonal flu, even if the authors note that it was the most severe of the last five years in France.