The research, using French national data and lead by a French team, and published in the journal The Lancet Respiratory Medicine on Friday, underscored the increased severity of illness for people with Covid-19.
Researchers compared data for 89,530 patients hospitalised with Covid-19 in March and April this year with 45,819 patients hospitalised with seasonal influenza between December 2018 and the end of February 2019.
Some 16.9 percent of Covid-19 patients died during the period of study – which was during the first wave of the virus. The second wave has seen some improvements in medical treatments which have lowered the number of Covid patients ending up in intensive care.
This compares to a death rate of 5.8 percent among those with influenza.
Catherine Quantin, a professor at the University Hospital of Dijon and the French national health institute INSERM who jointly led the study, said the difference in death rates was “particularly striking” given the 2018/19 flu season was the deadliest France had seen in five years.
The authors note that the difference in the number of hospitalisations – which saw twice as many people admitted for Covid-19 than flu – may be partly explained by existing immunity to influenza, either because of previous infection or vaccination.
Researchers found that more patients with Covid-19 needed intensive care – 16.3 percent compared with 10.8 percent for influenza – while the average stay in ICU was nearly twice as long (15 days compared to 8 days).
The study also reported far fewer children under 18 hospitalised with Covid-19 than with flu – 1.4 percent compared to 19.5 percent.