Eosinophilia in critically ill COVID-19 patients: a French monocenter retrospective study

As reported in bacterial sepsis [ 1 ], the early phase of SARS-CoV-2 infection seems to be accompanied by eosinopenia [ 2 , 3 , 4 ]. Conversely, our team noticed that several of our critically ill COVID-19 patients developed unexpected and unexplained eosinophilia during their ICU stay. Indeed, as white blood cells count is performed almost daily, monitoring and studying eosinophil course is simple in the ICU setting. To our knowledge, no study has focused on eosinophilia in COVID-19 although eosinophil recovery seven days after initial eosinopenia seems to be associated with a better outcome [ 3 ].