However, it is noteworthy that 19 patients in Group 1 used triple antiviral therapy all the time, whose nucleic acid tests were continuous positive. But, after use of combined chloroquine phosphate, all these patients ‘nucleic acid tests became negative for SARS-CoV-2 antigens, so they were discharged within 10 days. 5(14.3%) patients’ nucleic acid test turned positive again, even after they were discharged from the

Compared with Group 2, Group 1 had higher percentage of oxygenation index < 300 mmHg (8 [22.9%] vs 4 [6.5%]), more leucopenia (white blood cell count <4 × 109 /L, 5 [14.3%] vs 4 [6.5%]), and more lymphopenia (8 [22.9%] vs 1[1.6%]), lymphocyte count <0.8×109 /L, Table 3).

Table 3: The laboratory findings of 97 patients with SARS-Cov-2 infection (on admission).

The percentages of C-reactive protein ≥8mg/L, Procalcitonin ≥ 0.5ng/ml, D-dimer ≥1mg/ml and alanine aminotransferase≥40U/L were higher in Group 1 than in Group 2 (16 [45.7%] vs 13 [21%],6 [17.1%] vs 5 [8.1%], 7[20%] vs3[4.8%],and 8 [22.9%] vs 4 [6.5%],respectively, Table 3).

Discussion

Since an outbreak of pneumonia caused by SARS-CoV-2 was reported in December 2019, many researchers have found that SARS-CoV-2 can cause sustained human-to-human transmission in other areas, thus resulting in global outbreak with a certain mortality rate, seriously threatening human health [7-11].

This study showed that of the 97 confirmed patients, only 4 had been admitted to the intensive care unit, and no patients died. 6 patients’ nucleic acid tests were confirmed to return to positive again after discharge from the hospital, but they had no any symptoms at that time, who continued to receive antiviral therapy and the nucleic acid test turned negative again within 10 days. In this study, only 8 confirmed patients had been to Wuhan city. Most of them were infected by family gathering or close contact with patients confirmed with SARS-CoV-2 infection [12].

Of all the patients, the most common symptoms were fever (39.2%), cough (48.5%), sputum production (29.9%) and diarrhea (19.6%); most of them were regarded as mild and moderate type, but some had organ function injury, including ARDS, acute cardiac injury, and acute liver injury. Only 4.1% patients had been admitted to ICU. All the patients were discharged and no one died. Compared with those initially infected with SARS-CoV-2 in Wuhan, patients in Guizhou province had milder symptoms, better prognosis and lower mortality [13,14] indeed.

In this study, 46.4% of patients were treated with dual antiviral therapy, 24.7% with triple antiviral therapy, and 23.7% with quadruple antiviral therapy. Therefore, combination of antiviral therapy was major choice.

In our province, most of the COVID-19 patients had stayed in hospital for more than 10 days, so we divided the cohort into two groups: patients with hospitalization for more than 20 days (Group 1) and those with hospitalization for less than 20 days (Group 2). To our knowledge, this is the first time we compared the clinical data between the two groups above at home and abroad.

Compared with Group2, Group1 had more acute respiratory distress syndrome, hospital-acquired infection as secondary infection, suggesting that these two complications may lead to longer stay in hospital; more patients received quadruple antiviral therapy, antibiotic therapy and immune enhancer in Group 1, so we think longer hospitalization is usually accompanied by more powerful treatment.  In Group1, 2 patients were treated by convalescent plasma therapy and high-flow nasal cannula, with 1 administered plasma exchange [4]. Patients had been admitted to ICU. 14.3% of the patients had the nucleic acid tested after discharged from hospital, which showed positive again. So, we think those repeated positives are common in patients with longer stays in hospital.

Compared with Group2, Group1 had lower oxygenation index and higher percentages of leucopenia, lymphopenia, C-reactive protein≥8mg/L and procalcitonin≥ 0.5ng/ml, suggesting that higher severity of disease is one of reasons for the longer hospitalization days and that inflammation may be a factor of discharge delays.

In contrast to those of Group2, the percentages of D-dimer and alanine aminotransferase ≥40U/L were higher in Group1, which is consistent with some related studies that higher levels of D-dimer and aminotransferase were associated with severity of disease in critically ill patients [15,16].

Figure 2: Chest CT images of one man with SARS-Cov-2 infection. Transverse chest CT images of one man with SARSCoV-2 infection revealed bilateral ground-glass opacity in both lungs on admission on February 15, 2020. (Fig. 2 A, B). After antiviral therapy, Transverse chest CT images from the patient with SARS-CoV-2 infection showed bilateral ground glass opacity were obviously absorbed on February 21, February 25, and March 1, 2020 (Fig. 2 C, D, E, F, G, H).

Conclusions

COVID-19 patients with longer hospitalization are more severe and need more quadruple antiviral therapy; for patients who don’t use chloroquine phosphate, the nucleic acid tests may be more likely to return to positive again even if they have no symptoms at that time.

It is noteworthy that 19 of the 35 patients in Group1 used triple antiviral therapy all the time, but their nucleic acid tests were continuous positive; after treated with combined chloroquine phosphate, these patients’ nucleic acid tests became negative for SARS-CoV-2 antigens again. In addition, 5 patients who hadn’t received any treatment with chloroquine phosphate, were confirmed to have positive nucleic acid testing again even after they were discharged from hospital. So, we speculate that chloroquine phosphate as one antiviral therapy against SARS-CoV-2 infection might be superior to other antiviral treatments [17,18]. But due to small sample size of this study, the larger sample size is needed to draw a more accurate conclusion in the near future (Figure 2).

Declarations Authors’ Contributions

Xianwei Ye and Xiangyan Zhang conceptualized and designed the research. Yiling Zhang and Cheng Zhang collected the data and wrote the article. Hongmei Yao analysed the data. Li Zhao, Ying Hu and Xianchun Zeng helped to collect the data. All the authors have read and approved the final manuscript.

Funding

This study was supported by the National Natural Science Foundation of China (Nos. 81860008); Natural Fund of Guizhou Provincial Science and Technology Department (Nos. (2018)1104), and Guizhou Science and Technology Cooperation Support Project (Nos. [2020]4Y002, [2019]5803). The fund is from the national and local Government. They act just as one of supervisors.

Availability of Data and Materials

All the data and materials are included in the article.

Ethics Approval and Consent to Participate

This study was approved by Ethics Committee of Guizhou Provincial People’s Hospital. Since it is a retrospective study and only data were used, the ethics committee waived the need for written informed consent from the participants.

Competing Interests

The authors declare that no financial benefits and commercial relationships have been received or will be conducted to this article.

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