Demographics and clinical characteristics
A total of 79 patients with COVID-19 were included in this study (42 men, 37 women), with median age of 48.0 (39.0-59.0) years. Among them, there were 73 moderate cases (38 men, 35 women) with median age of 47.0 (38.5-57.5) years, 5 severe cases, 1 critical case, and no mild case on admission. The mortality rate (66.7%, 4/6) in severe/critical patients was higher than that (1.4%, 1/73) in moderate patients, whereas there were no significant differences with respect to exposure history, occupation, smokers, comorbidity and so on between moderate patients and severe/critical patients (Supplementary table 1, Figure 1A).
The most common symptoms at disease onset were cough (72.6%), fever (38.4%), chest tightness (34.2%), fatigue (21.9%), and gastrointestinal symptoms (19.2%), and other less common symptoms included dizzy/ headache (12.3%), nasal obstruction (8.2%), chill (2.7%), and runny nose (1.4%) in 73 moderate patients. Only one case developed complications (acute respiratory distress syndrome and acute heart failure) in 73 moderate patients that was less common compared with 6 severe/critical patients (Supplementary table 2).
The main symptoms cough, fever, chest tightness, and fatigue during hospitalization lasted for 11.0 (9.3-17.0), 8.0 (5.0-12.0), 11.0 (8.0-12.0), and 7.0 (4.5-8.5) days, respectively, and the duration of positive nucleic acid test (NAT) results for SARS-CoV-2 was 16.5 (12.0-22.0) days in 72 moderate survivors with COVID-19. The median median length of hospital stay was 25.0 (18.0-29.5) days; the median time from disease onset to discharge was 29.5 (25.0-36.5) days (Table 1). The duration of cough (r=0.426, P=0.002) and fever (r=0.543, P=0.003) was positively correlated with the duration of the positive NAT results, but the duration of chest tightness (r=0.238, P=0.275) was not correlated with the duration of the positive NAT results in 72 moderate patients (Figure 2).
Laboratory and imaging findings in 72 moderate survivors with COVID-19
On admission, most patients had the normal range of leucocytes (79.2% cases), neutrophils (86.1% cases), and neutrophil percentage (72.2% cases), but a small minority of patients had decreased leucocytes (19.4% cases) and increased neutrophil percentage (26.4% cases). Lymphocytes and lymphocyte percentage were below the normal range in 50.0% of the patients and 40.3% of the patients, respectively. Platelets were within the normal range in 88.9% of the patients, and a small number of patients had decreased platelets (11.1% cases) (Table 2).
More than half of the patients had a increased level of C-reactive protein (CRP) (65.3% cases), with median CRP level 14.1 mg/L (3.5-29.3). Procalcitonin (PCT) level was within the normal range in 95.8% of the patients (Table 2).
On admission, all patients showed the normal prothrombin time and the normal activated partial thromboplastin time. The D-dimer level was within the normal range in 87.5% of the patients (Table 2).
The fasting blood glucose (FBG) level was within the normal range in 79.2% of the patients, with 20.8% increased FBG on admission. Most of the patients had the normal liver function, with 27.8% decreased albumin (ALB) level and 13.9% increased aspartate aminotransferase (AST) level. Almost all patients had the normal range of creatine kinase (CK) and isoenzyme of creatine kinase (CKMB) levels, and most of the patients had the normal range of lactate dehydrogenase (LDH), with 19.4% increased LDH level. All patients had the normal range of blood urea nitrogen (BUN) and creatinine levels (Table 2).
At discharge, the abnormal laboratory results of the 72 survivors were significantly improved, but there were still some patients who had the abnormal laboratory findings (6.9% decreased leucocytes, 9.7% increased neutrophil percentage, 26.4% decreased lymphocytes, 18.1% decreased lymphocyte percentage, 12.5% increased CRP level, 6.9% increased FBG level, 37.5% decreased ALB level, 8.3% increased AST level, and 4.2% increased LDH level) compared with those on admission (Table 2).
On admission, 72.2% of the patients had bilateral viral pneumonia, and the remaining 27.8% patients had unilateral viral pneumonia in chest CT images. At discharge, the CT scans were negative in 20.8% of the patients, and the acute exudative lesions were improved significantly in the remaining 79.2% patients (Table 1). The representative chest CT images of the moderate survivors were presented in Figure 3.
Main treatment regimen
All moderate patients received antiviral therapy, including combination of interferon-α and lopinavir/ritonavir tablets or combination of interferon-α and abidol or combination of interferon-α and ribavirin; 34.7% of the moderate patients were given corticosteroid treatment (methylprednisolone or budesonide); 44.4% of the moderate patients were administered with empirical antibiotic treatment (cephalosporins or quinolones). 55.6% of the moderate patients received oxygen support by nasal cannula. Moreover, 91.7% of the moderate patients were administered with traditional Chinese medicine (Lianhua Qingwen granules or Qingfei Paidu decoction or Cold Dampness and Stagnant Lung decoction) (Table 1 and Supplementary table 3).
Follow up results in 72 moderate survivors with COVID-19
At the end of a 14-day medical observation, all survivors had no clinical symptoms, and the NAT showed that 4 (5.6%) of the patients had the re-positive results and 68 patients had the negative results after recovery in 72 moderate survivors. Chest CT scans were performed after undergoing another 14-day self-imposed quarantine at home in the 68 patients with the negative NAT results, and the result showed the acute exudative lesions were completely absorbed in 72.1% (49/68) of the patients, and the lesions were further improved in the remaining 27.9% (19/68) patients. At this point, the 68 patients were released from isolation (Table 1, Figure 1A).
The 4 patients with re-positive NAT results returned to the hospital for further treatment using the aforementioned regimen. They were 3 women and 1 man, with median age of 60.0 (41.3-72.8) years (Supplementary table 4). All 4 patients had no clinical symptoms (Supplementary table 5). On re-admission, almost all the laboratory results including blood routine, infection biomarkers, coagulation function, and blood biochemistry were within the normal range, and there were no significant changes on chest CT images compared with those at discharge (Supplementary table 5 and Supplementary table 6). They underwent the median length of re-hospital stay of 8.5 (6.5-10.5) days, and were re-discharged after having 2 consecutive re-negative NAT results for SARS-CoV-2 with at least one-day interval. Subsequently, the 4 patients re-underwent a 14-day collective medical observation and another 14-day self-imposed quarantine at home. The 4 patients had the re-negative NAT results and the negative chest CT images 14 days and 28 days after re-discharge, respectively (Supplementary table 5, Figure 1, Supplementary figure 1 ).