Discussion
This present study showed that COVID-19 patients with a history of traveling in Wuhan had some clinical characteristics and laboratory parameters that were different from COVID-19 patients who did not travel in Wuhan. Lymphocytopenia, including the reduced CD3+, CD4+ and CD8+ T cell counts on hospital midterm were observed in Wuhan patients and percentage of severe to critical cases in WH patients was significantly higher than that in NWH patients, implying decrease in lymphocyte was related to the severity of the disease, which is in agreement with the statement by Zhang et al 8. The observation that patients with COVID-19 with a history of traveling in Wuhan more prone to severe diseases could be explained from two aspects, firstly, SARS-CoV-2 might evolve adaptations to optimize its fitness to novel hosts during human-to-human transmission, and viral adaptation may increase its transmissibility but attenuate its pathogenesis, similar pattern have also been observed in Ebola virus9. Since mutations are part of the convergent evolution, it would be interesting to investigate the dynamic intra-host genomic variations of SARS-CoV-2 during the transmission process of COVID-19 patients. Secondly, after the outbreak in Wuhan, the local CDC strengthened the screen of COVID-19 patients, especially those with a traveling history to Wuhan and close contacts with confirmed cases, early identification and treatment is an efficient tactics to avoid the development of severe diseases.
Acknowledgments
The authors thank all the staff working in the Department of Infectious Diseases from Shenzhen Third People’s Hospital for providing COVID-19 clinical data.
Funding This work was supported by the National Science and Technology Major Project for Control and Prevention of Major Infectious Diseases of China (No. 2017ZX10103004), the Guangdong Scientific and Technological Project (NO. 2020B1111340076), and the Shenzhen Bay Laboratory Open Project (No. SZBL202002271003).