Research Square · Oct 20, 2021
Association between low eosinophil count and mortality in SARS-COV-2 infection on the 70+, a discussed observation
By Baudouin É, Kosowki J, Mésinèle L et al.
Abstract Background: Biological COVID-19 abnormalities are varied (lymphopenia, high levels of blood inflammatory markers, …). Regarding physiological immune responses, eosinophils were for a long time thought to be mainly against extra-cellular pathogen like helminthes. It has recently been pointed out that they appear to play a part in recognition of virus and to have the capacity to perform direct action against viruses. This study aimed to seek for an association between eosinophils count < 10 /mm3 and mortality in an older adults suffering from COVID-19 hospitalized in a specific geriatric ward. Methods: This observational retrospective study was conducted in a French geriatric ward from March 17 to April 18, 2020. All 118 patients hospitalized for COVID-19 over 70 yo in acute stay care were enrolled. Patients with a treatment or a condition which could interfere with eosinophil count were excluded. Results: No statistical difference was found between surviving or deceased patient regarding age (mean age (SD): 87 years (7)) and sex (34% of males). Differences for the most frequent acute events were statically different: Quick Sepsis-related Organ Failure Assessment (qSOFA) score was ≥ 2 at admission for 23% in the survivor group vs 72% in the deceased (p < .001); acute kidney injury concerned 17% of the survivors vs. 69% of the decease (p< .001). Eosinophil count < 10/mm3 was significantly associated with mortality (OR (95% CI)) = 3.54 (1.23-11.4) after adjustment on age, gender, and activity of daily living.Conclusion: Low eosinophil count (< 10/mm3) seems to be associated with mortality on older adults. Due to the specific physiological ageing process of the immune system, this calls to explore more globally the impact of inflammaging and immunosenescence on SARS-CoV-2 infection in this population.