Coronavirus three times more deadly than flu in hospitalised patients, new study finds

The death rate among hospitalised Covid-19 patients is three times higher than that of people admitted for the flu, according to a new study.

The review, published in the Lancet Respiratory Medicine journal, saw researchers compare national French data from 89,530 coronavirus patients admitted to hospital over a two-month period in spring 2020, with 45,819 flu patients admitted over a three-month period during the seasonal flu outbreak of 2018-19.

Among several revelations was that 15,104 of those hospitalised in France with Covid died as a result of the virus, whereas 2,640 succumbed to the flu. 

It was also discovered that a greater percentage of coronavirus patients (16.3 per cent) experienced severe illness, usually requiring intensive care, than those with the flu (10.8 per cent).

Professor Catherine Quantin, from L’Institut National de la Santé et de la Recherche Médicale (Inserm), was one of the study’s lead authors. She said it was “the largest to date to compare the two diseases and confirms that Covid-19 is far more serious than the flu”, in a blow to the NHS and other healthcare systems which are braced to see the two viruses cross over in the cold months ahead.

“The finding that the Covid-19 death rate was three times higher than for seasonal influenza is particularly striking when reminded that the 2018-19 flu season had been the worst in the past five years in France in terms of number of deaths,” she added.

The paper showed that while in French hospitals, more than one in four Covid patients experienced acute respiratory failure – where the lungs are unable to get oxygen into the body – compared with less than one in five patients with influenza.

Covid patients were also more than twice as likely as flu patients (9.7 per cent vs 4 per cent) to require invasive mechanical ventilation as part of their hospital treatment, the study showed. Even the length of stay in intensive care units was longer for coronavirus patients, who averaged 15 days, while flu patients averaged eight. 

Where the flu does appear to be more serious than coronavirus is in younger people, with researchers observing that just 1.4 per cent of children aged under 18 were hospitalised with coronavirus as opposed to the 19.5 per cent who were admitted with the flu. 

Additionally, the fatality rate for both illnesses was found to be very low in those aged five and under, with figures showing that just three of those admitted to intensive care units died from coronavirus; 13 died from the flu.

A larger proportion of Covid patients under the age of five did, however, require more intensive care support than did those with influenza (2.3 per cent vs 0.9 per cent). 

The study, authored by Prof Quantin and two other medical researchers, is based on data from the French national administrative database (PMSI). The three compared Covid-19 hospitalisations between 1 March and 30 April 2020 with seasonal flu hospital admissions between 1 December 2018 and 28 February 2019.

Dr Pascale Tubert-Bitter, research director at Inserm, who jointly led the study, said: “Taken together, our findings clearly indicate that Covid-19 is much more serious than seasonal influenza.” 

She added: “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.”

The paper’s findings come as French president Emmanuel Macron tested positive for coronavirus on Thursday, after returning from Brussels where he met with all EU member state leaders at a summit. 

Mr Macron’s infection was announced by his office just as France was easing out of its latest lockdown, with new cases now running around 11,000 a day, down from their recent spike of 86,000 in early November.