Analysis Of Dynamic Changes Of Eosinophil Count In Peripheral Blood Of Patients With COVID-19

Background:The novel coronavirus disease 2019（COVID-19）is a highly contagious disease that has spread rapidly around the world since it was first reported.It has brought great harm.Some patients rapidly progressed to acute respiratory distress syndrome（ARDS）and even died.The fatality rate reached 2%to 3%,and the new coronavirus（SARS-Co V-2）Mutation is fast.In order to reduce the fatality rate of new coronavirus pneumonia,it is particularly important to find effective clinical monitoring methods for early diagnosis of new coronavirus pneumonia and prediction of disease severity.In clinical work,we found that the proportion of eosinophils（eosinophils,EOS）decreased in the early stage was relatively high,and the EOS count changed with the change of the condition,but whether the change of EOS count can be used as a clinical diagnosis of new coronavirus pneumonia and the indicators of disease assessment need further in-depth study.Objective:To explore the clinical significance of dynamic changes of eosinophil count in peripheral blood of COVID-19 patients.Methods:The eosinophil counts of 478 COVID-19 patients admitted to Suizhou Central Hospital from January to March 2020 were retrospectively analyzed.478 patients with COVID-19were included in the new crown group,and 480 patients with community-acquired pneumonia（CAP）not caused by the new coronavirus admitted to Suizhou Central Hospital from November 2019 to July2021 were used as CAP group;at the same time,479 healthy people with physical examinations from July 2020 to July 2021 in the Suizhou Central Hospital Health Checkup Center were used as the healthy control group.According to the outcomes of COVID-19 patients,the patients with COVID-19 were divided into survival group and death group;according to whether the EOS count on admission was lower than normal,they were divided into EOS normal group and EOS decreased group.The dead patients were divided into EOS recovery group and EOS non-recovery group according to whether the EOS count returned to normal after admission and treatment.The proportion of EOS count,lymphocyte（LYM）count,and leukocyte（LEU）count lower than normal in the new crown group and CAP group was counted,and the EOS count,LYM count,and LEU count of COVID-19 patients in the survival group and the death group were compared.Characteristics,draw a line chart of the change trend of EOS count over time after admission and treatment in the death group and the survival group.The relationship between the hospitalization time,body temperature recovery time,EOS count recovery time,lung CT image improvement time,and SARS-Co V-2 virus nucleic acid conversion time of patients with normal EOS and decreased EOS were analyzed and compared.Plot the survival curves of COVID-19 patients in the EOS recovery group and the EOS non-recovery group during hospitalization.Results:1.The proportion of EOS count,LYM count,and LEU count lower than normal in the new crown group at admission were 55.2%,55.0%,and 39.7%,which were significantly higher than those in the CAP group（23.7%,26.6%,15.4%）and the control group（2.0%,6.6%,6.4%）,all P<0.01;the proportion of EOS counts lower than normal in the new crown group was significantly higher than the proportion of LEU counts lower than normal（P<0.01）,and the proportion of LYM counts lower than normal was significantly higher than that of LYM counts.The proportions were comparable（P>0.05）.2.The proportion of COVID-19 patients with EOS count lower than normal in the death group was 91.8%,which was significantly higher than that in the survival group（53.7%）,P<0.01.3.The EOS count of the COVID-19 patients in the survival group rebounded rapidly with the improvement of their condition,while the EOS count of the COVID-19 patients in the death group remained at a low level with the prolongation of hospitalization（the median EOS count was 0.02×10~9/L）,P<0.05.4.The median time of body temperature recovery in the reduced EOS group was significantly longer than that in the normal EOS group（4.0d vs 2.0d,P<0.01）.The median time for EOS count recovery in the EOS-lowering group was 5.0 days,which was earlier than the time for improvement of chest CT images（11.0 days,P<0.05）and the time for viral nucleic acid to turn negative（15.0 days,P<0.05）.5.The patients in the EOS non-recovery group had a shorter mean survival time within 40 days than the patients in the EOS recovery group（13.5d vs 17.0d,P<0.05）.Conclusion:Subnormal eosinophil counts are an important feature of COVID-19 patients and are more common than subnormal white blood cell counts and comparable to subnormal lymphocyte counts.COVID-19 patients with lower eosinophil counts on admission took longer to recover their body temperature than those with normal eosinophil counts.The eosinophil count recovered with the recovery of the COVID-19 patient’s condition,and the recovery was earlier than the improvement of the chest CT image and the negative viral nucleic acid.COVID-19 patients with severe and persistently low eosinophil counts have a poor prognosis.