Table 1. A severity level for patients with COVID-19 infection; Adapted from reference no 10.

Severity level	Signs and symptoms
1. Asymptomatic	Asymptomatic
2. Mild COVID-19	Signs and symptoms of respiratory tract infection or gastrointestinal symptoms without pneumonia
3. Moderate COVID-19	Pneumonia that did not fulfill the criteria of severe COVID-19
4. Severe COVID-19	Pneumonia with oxygen saturation at room air < 90%* Tachypnea > 30 per minute in adults or children > 5 years old > 60 per minute in children < 2 months > 50 per minute in children 2–11 months > 40 per minute in children 1–5 years old Severe respiratory distress
4. Critical COVID-19	Requiring mechanical ventilation, inotropes, or vasopressors Fulfilled the criteria for acute respiratory distress syndrome or septic shock

*Caution: An oxygenation saturation of 90–94% at room air might be an early sign for patient deterioration. These patients were considered to have severe disease if requiring respiratory support.