Patients and study design
Only COVID-19 patients who met all the following criteria(National_Health_Commission_of_China, 2020 ) could be discharged from the hospital and admitted to the follow-up study project: (1) body temperature returned to normal for more than 3 consecutive days, (2) had significant improvement in any symptom, such as fever, dry cough and expectoration, (3) had substantial improvement in acute exudative lesions on chest computed tomography (CT) images, and (4) had negative RT-PCR test results for SARS-CoV-2 RNA from a nasopharyngeal swab, an anal swab or other respiratory specimens two consecutive times (at least 24 hours apart).
Between January 30, 2020, and September 9, 2020, a total of 745 patients who officially recovered from COVID-19 were discharged from the hospital and enrolled in this study in Guangzhou, China. All discharged patients were required to undergo 14 days of quarantine in designated health care facilities and 28 days of community follow-up to observe their clinical symptoms and RT-PCR results. The positive retest patients were re-admitted to the hospital for therapy, and close contacts were traced and followed-up. The remaining discharged patients who continued to have negative RT-PCR test results were closely followed-up in their communities. Fig. 1 shows the flowchart of the management of discharged patients.
This study was reviewed and approved by the Ethics Committee of the Guangzhou CDC (GZCDC). As required by the National Health Commission of China, CDCs were responsible for the work for an ongoing public health response to COVID-19, and our cohort study was based on the data from the GZCDC. Patients were informed about the surveillance before providing written consent, and data were collected and anonymized for analysis. All analyses of personally identifiable data took place onsite at the GZCDC.