Prevalence and clinical features of 2019 novel coronavirus disease (COVID-19) in the Fever Clinic of a teaching hospital in Beijing: a single-center, retrospective study

Ying Liang; Jingjin Liang; Qingtao Zhou; Xiaoguang Li; Fei Lin; Zhonghua Deng; Biying Zhang; Lu Li; Xiaohua Wang; Hong Zhu; Qingbian Ma; Xiaomei Tong; Jie Xu; Yongchang Sun

A unique feature of our study was the comparison between COVID-19 and non-COVID-19 cases visiting the same Fever Clinic at a certain period, with the finding that the total WBC count and the neutrophil count were different between the two groups of patients. Increased total WBC and neutrophil counts were more common in patients with other causes of pneumonia. In contrast, although decrease of lymphocytes was also common in our study, the difference between COVID-19 and non-COVID-19 cases was not significant, probably due to the fact that pneumonias enrolled for this analysis were mostly viral(for example, influenza) or atypical, as classical bacterial pneumonia had been excluded by first screening/triage. Additionally, the percentage of our patients with decreased lymphocytes was not as high as that reported in some previous studies 2, 15 , perhaps due to differences in disease severity. Blood lymphopenia was observed in up to 85% of critically ill patients with COVID-19 16 . Compared with mild and moderate cases, severe cases were more likely to have lymphopenia 2,16,17 . A recent paper by Xu and colleagues showed a lymphocyte decrease in 38% of the cases within symptom onset ≤ 10 days 18 , which was consistent with our data. Therefore, we speculate that persisting decrease of lymphocytes may be an indicator of severe disease, rather than a criterion for the diagnosis of COVID-19.