Table 1.

Characteristics of different scores.

	Dong et al. [7]	Gale et al. [11]	Venturini et al. [15]	Kanburoglu et al. [16]
Mild	Symptoms of acute upper respiratory tract infection or digestive symptoms		Fever and/or fatigue and/or upper airways symptoms without radiological/ultrasound findings	Upper respiratory tract infection or fever, no feeding difficulty and no obvious hypoxemia, and no risk of late neonatal sepsis
Moderate	Pneumonia without hypoxemia and shortness of breath Chest computed tomography abnormalities without clinical signs and symptoms		Fever and/or fatigue and/or upper airways symptoms (cough or mild respiratory distress) and/or poor feeding and/or pneumonia identified with chest X-ray or ultrasound	Hospitalization due to feeding difficulty or risk of late neonatal sepsis, but no obvious hypoxemia or no need for nasal continuous positive airway pressure
Severe	Oxygen saturation is <92% with other hypoxia manifestations	At least two of the following: (1) any of hyperthermia, apnea, cough, tachypnoea, respiratory distress or recession, supplemental oxygen requirement, poor feeding or vomiting, or diarrhea; (2) any of low white blood cell count, low lymphocyte count, or raised C-reactive protein concentration; and (3) abnormal chest X-ray	Fever and cough, plus at least one of the following: (1) oxygen saturation on finger pulse <92% on room air; (2) severe respiratory distress, cyanosis, intermittent apnea; (3) fast breathing; (4) systemic symptoms: drowsiness, lethargy, seizures, dehydration	Oxygen saturation <92% or need for nasal continuous positive airway pressure
Critical	Acute respiratory distress syndrome, respiratory failure, shock, encephalopathy, myocardial injury or heart failure, coagulation dysfunction, and acute kidney injury		Pediatric acute respiratory distress syndrome, sepsis-associated organ dysfunction, septic shock, coma	Mechanical ventilation or disseminated intravascular coagulopathy or multiple organ dysfunction