Introduction
A novel human coronavirus which is a new strain of RNA viruses was recognized in Wuhan, China, in Dec. 2019. The novel coronavirus is now officially named SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) by International Committee on Taxonomy of Viruses (ICTV). The pneumonia caused by SARS-CoV-2 has been recently identified as COVID-19 (coronavirus disease 2019). COVID-19 spread quickly across Hubei Province and other regions of China,1 , 2 also the global alert for COVID-19 has been issued by the World Health Organization (WHO).1 , 2 COVID-19 could induce symptoms including fever, dry cough, dyspnea, fatigue and lymphopenia in patients, and might result in severe acute respiratory syndrome (SARS) and even death in severe cases.1, 2, 3
SARS-CoV-2 belongs to the beta-coronavirus 2b lineage in the phylogenetic tree and shares ∼80% identity sequencing with the Bat SARS-like coronavirus and the original SARS epidemic virus.4 , 5 Currently, it remains to be determined the origins and possible intermediate animal vectors of SARS-CoV-2, as well as the mechanism that this virus spread among humans. Despite many reports have characterized the clinical, epidemiological, laboratory, and radiological features, as well as treatment and clinical outcomes of patients with COVID-19 pneumonia, the information of the SARS-CoV-2 reactivation remains not reported. The curative and eradicative therapy for COVID-19 is not currently available. Urgent questions that need to be addressed promptly include whether patients with COVID-19 pneumonia will reactivate, and whether risk factors predict SARS-CoV-2 reactivation in patients. To prevent and control COVID-19 reactivation, we retrospectively collected and analyzed detailed clinical data from SARS-CoV-2 reactivated patients. In the study, we presented clinical features of SARS-CoV-2 reactivated patients and discussed the potential risk factors of SARS-CoV-2 reactivation.