In the present invention, inventors investigate the representation of neutrophil subsets in severe and critical COVID-19 patients based on Intensive Care Units (ICU) and non-ICU admission. The results show that 80% of ICU patients develop strong myelemia with CD10-CD64+ immature neutrophils. Cellular profiling revealed two distinct neutrophil subsets expressing either the LOX?1 or CD123 marker, both overrepresented in ICU patients compared to non-ICU patients. The proportion of LOX-1-expressing immature neutrophils positively correlated with clinical severity, with the cytokine storm (IL-1?, IL-6, IL-8, TNF?), and with intravascular coagulation. Importantly, high proportions of LOX-1+-immature neutrophils are associated with higher risk of severe thrombosis. The present invention relates to non-invasive, specific and rapid methods for prognostic and monitoring the severe / critical form of coronavirus infection. More specifically present invention relates to methods for prognosis and/or monitoring of the critical form of coronavirus infection through detection of a specific population of neutrophils in a covid patient. The present invention also relates to a method of preventing or treating a coronavirus infection in a subject in need thereof