Figure 2个  Table 5
    • Clinical characteristics (n = 131)
      Sex (Male/Female) 90 (68.7%)/41 (31.3%)
      Age, years 51.4 ± 11.8 (24–81)
      Age range, years
        24–39 19 (14.5%)
        40–59 76 (58.0%)
        60–79 35 (16.7%)
        ≥ 80 1 (0.8%)
      Days from onset to hospitalization 9.04 ± 3.93 (1–24)
      Time of staying in hospital (days) 18.26 ± 10.06 (4–72)
      Normal/severe/critical cases 15 (11.4%)/82 (62.6%)/34 (26.0%)
      Comorbidities 55 (42%)
        Hypertension 31 (23.7%)
        Diabetes mellitus 14 (10.7%)
        Heart disease 7 (5.3%)
      Epidemiologic history
        History of residence or travel 131 (100%)
        Exposure to Huanan Seafood Wholesale Market 75 (57.3%)
        History of contacting with COVID-19 patients 12 (9.2%)
        Clustered onset 9 (6.9%)
      Onset symptoms
        Fever 124 (94.7%)
        Cough 96 (73.3%)
        Dyspnea 50 (38.2%)
        Fatigue 43 (32.8%)
        Shortness of breath 33 (25.2%)
        Gasping 22 (16.8%)
        Muscle ache 20 (15.3%)
        Headache 15 (11.5%)
        Chill 12 (9.2%)
        Chest pain 7 (5.3%)
        Nausea 5 (3.8%)
        Dizziness 5 (3.8%)
        Sore throat 4 (3.1%)
        Runny nose 4 (3.1%)
        Difficulty breathing 4 (3.1%)
        Joint soreness 4 (3.1%)
        Palpitations 3 (2.3%)
        Vomit 3 (2.3%)
        Shivering 3 (2.3%)
        Diarrhea 2 (1.5%)
      Treatment
        Glucocorticoids 64 (48.9%)
        Immunoglobulin 19 (14.5%)
        High-flow Nasal Cannula 33 (25.2%)
        Non-invasive ventilation 16 (12.2%)
        Invasive ventilation 7 (5.3%)
        Extracorporeal membrane oxygenation 4 (3.1%)
        Renal replacement therapy 6 (4.6%)
        Blood transfusion 4 (3.1%)
        Vasoconstrictive agents 4 (3.1%)
      Complication 72 (55.0%)
        Liver dysfunction 48 (36.6%)
        Acute respiratory distress syndrome 40 (30.5%)
        Hypoproteinemia 34 (26.0%)
        Sepsis 18 (13.7%)
        Thrombocytopenia 16 (12.2%)
        Acute kidney injury 13 (9.9%)
        Septic shock 11 (8.4%)
        Acute myocardial injury 9 (6.9%)
      In-hospital mortality 15 (11.5%)

      Table 1.  Demographics and clinical characteristics of the included patients.

    • Parameter
      White blood cell count, × 109/L 6.02 ± 3.30
         < 3.5 25/131 (19.1%)
        3.5 ~ 9.5 88/131 (67.2%)
         > 9.5 18/131 (13.7%)
      Neutrophil count, × 109 /L 4.66 ± 3.38
      Lymphocyte count, × 109 /L 1.00 ± 0.52
         < 1.1 83/131 (63.4%)
        ≥ 1.1 48/131 (36.6%)
      C-reactive protein, mg/L
         < 5 21/128 (16.4%)
        ≥ 5 107/128 (83.6%)
      Procalcitonin, ng/mL
         < 0.5 123/128 (96.1%)
        ≥ 0.5 5/128 (3.9%)
      ESR, mm/h 49.82 ± 5.06
         < 15 7/127 (5.5%)
        ≥ 15 120/127 (94.5%)
      Interleukin6, pg/mL 8.10 ± 5.80
         < 7 48/97 (49.5%)
        ≥ 7 49/97 (50.5%)
      Ferritin, ng/mL
         < 274.66 33/119 (27.7%)
        ≥ 274.66 86/119 (72.3%)
      LDH, mmol/L 326.14 ± 113.74
         < 250 43/128 (33.6%)
        ≥ 250 85/128 (66.4%)
      FIB, g/L 5.26 ± 1.91
         < 2 3/124 (2.4%)
        2 ~ 4 29/124 (23.4%)
        ≥ 4 92/124 (74.2%)
      D-Dimer, mg/L
         < 1.5 103/123 (83.7%)
        ≥ 1.5 20/123 (16.3%)
      Continuous data are expressed as mean ± SD. Categorical data are presented as n/N (%), where N is the total number of patients with available data.

      Table 2.  Laboratory parameters.

    • Days after onset Number of samples Number of positive for IgM by ELISA Number of positive for IgG by ELISA ELISA OD ratio of IgM ELISA OD ratio of IgG
      5 ~ 10 34 13 (38.2%) 22 (64.7%)* 0.202 ± 0.273 0.905 ± 0.808
      11 ~ 20 151 115 (76.2%) 147 (97.4%)* 0.431 ± 0.534 1.683 ± 0.653#
      21 ~ 30 35 28 (80.0%) 35 (100%)* 0.435 ± 0.493 1.686 ± 0.542#
      31 ~ 40 6 4 (66.7%) 5 (83.3%) 0.187 ± 0.103 1.621 ± 0.932#
      5 ~ 40 226 160 (70.8%) 209 (92.5%)* 0.391 ± 0.496 1.565 ± 0.722#
      *P < 0.05 versus IgM in the same period.
      #P < 0.05 versus 5 to 10 days.

      Table 3.  Differential sensitivity of ELISA for detection of IgM and IgG in different periods after disease onset.

    • Times of detection Number of patients Number of positive for IgM by ELISA Number of positive for IgG by ELISA
      1 36 26 (72.2%) 35 (97.2%)
      2 95 87 (91.6%)* 94 (98.9%)
      Total 131 113 (86.3%) 129 (98.5%)
      *P < 0.05 versus once.

      Table 4.  Differential sensitivity of ELISA for detection of IgM and IgG with different times in COVID-19 patients.

    • Negative to positive Positive to negative Positive twice Negative twice
      Number (%) of IgM change 30 (31.6%) 10 (10.5%) 47 (49.5%) 8 (8.4%)
      Number (%) of IgG change 11 (11.6%) 3 (3.2%) 80 (84.1%) 1 (1.1%)

      Table 5.  Dynamic changes of IgM and IgG in COVID-19 patients (n = 95).