BACKGROUND AND PURPOSE:

• Yang et al. (JAMA Netw Open., 2020) describe clinical characteristics of both symptomatic and asymptomatic patients with confirmed SARS-CoV-2 infection

METHODS:

• Case series (December 24, 2019, to February 24, 2020)
• Setting
  • Wuhan, China
• Participants
  • Consecutive hospitalized cases with lab confirmed COVID-19
  • Recruited from 26 cluster cases who had
    • Confirmed history of exposure to the Hunan seafood market or
    • Close contact with another patient who had been hospitalized for COVID-19
• Study design
  • RT-PCR on nasopharyngeal swabs was performed every 24 to 48 hours
  • CT scan: On admission with a second chest CT at 4 to 6 days and third CT at 6 to 7 days after the second scan
    • Additional CT for worsening status
  • CD4+T lymphocyte count was tested every 5 to 6 days

RESULTS:

• 78 patients
  • Median (IQR) number of patients per cluster: 3 (2-3) patients
  • Range: 2 to 10 patients per cluster
• Symptomatic vs asymptomatic
  • Symptomatic cases: 57.7% of cases (45 patients)
  • Asymptomatic: 42.3% of cases (33 patients)
• Patients who were asymptomatic tended to
  • Be younger (P < 0.001)
    • Asymptomatic: median (IQR) age 37 (26 to 45) years
    • Symptomatic: 56 (34 to 63) years
  • Be women (P = 0.002)
    • Asymptomatic: 66.7% were women (22 patients)
    • Symptomatic: 31.0% were women (14 patients)
  • Not have biochemical evidence of liver injury (P = 0.03)
    • Asymptomatic: 3% had a liver injury (1 patient)
    • Symptomatic: 20.0% had a liver injury (9 patients)
  • Have higher CD4+T lymphocyte counts  (P = 0.001)
    • Asymptomatic: median (IQR) 719 (538 to 963) per uL
    • Symptomatic: 474 (354 to 811) per ul
  • Have faster lung recovery based on CT scan (P = 0.001)
    • Asymptomatic: median (IQR) duration 9 (6 to 18) days
    • Symptomatic: 15 (11 to 18) days
  • Have a shorter duration of viral shedding on nasopharyngeal swabs (P = 0.001)
    • Asymptomatic: median (IQR) duration 8 (3 to 12) days
    • Symptomatic: 19 (16 to 24) days
  • Have more stable SARS-CoV-2 testing results
    • Asymptomatic: 12.1% had fluctuated results (4 patients)
    • Symptomatic: 33.3% had fluctuated results (15 patients)

CONCLUSION:

• Compared to symptomatic COVID-19 patients, asymptomatic patients experienced less organ injury and CT scans improved more rapidly
  • Consumption of CD4 lymphocytes was lower, suggesting less damage to the immune system
• Asymptomatic patients appear to have a shorter duration of viral shedding, suggesting that they may be infectious for a shorter period of time

Learn More – Primary Sources:

Comparison of Clinical Characteristics of Patients with Asymptomatic vs Symptomatic Coronavirus Disease 2019 in Wuhan, China

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