Comparison and Clinical Characteristics of COVID-19 in Different Time Period in Wuhan, China

Abstract Background SARS-CoV-2 is making deadly impact on the human lives all over the world. Therefore, we aimed to analyze the changes involved in clinical characteristics of COVID-19 patients over time. Methods We conducted a retrospective study to compare the patients whose onset of illness in January with the patients whose onset of illness in February in Wuhan, China.Results Among enrolled 896 patients, the median age was 60 years (47-69 years), 685 (76.5%) were categorized into group A (patients with illness onset in January), and 211 (23.5%) were categorized into group B (patients with illness onset in February). Compared with group B, group A had a higher rate of fever (p<0.001), the lower rate of asymptomatic (p<0.001). Group A had a higher incidence of neutrophilia (p=0.043), elevated D-miner (p<0.001), increased LDH (p=0.002), but lower incidence of normal CT scan (p=0.001). CD3 cells (p=0.015) and CD4 cells p=0.04) count significantly reduced in group A. Critical patients decreased (p=0.005) and mild patients increased (p=0.001) in group B. The fatality rate significantly decreased in group B (p=0.028).Conclusions The condition of patients with onset of illness in January were more serious than patients with onset of illness in February. It indicates that virulence showed reducing effect, but more basic research is required to support the hypothesis.