Clinical phenotypes of SARS-CoV-2 disease

TypeProportionClinical features
180–85% of symptomatic patientsFever, headache, mild respiratory symptoms, sore throat, no hypoxaemia, normal chest radiograph, excellent prognosis
2∼80% of hospitalised patientsMild hypoxia, minor (usually bilateral) infiltrates on chest radiograph, up to 15% may progress quickly to type 3
3∼15% of hospitalised patientsModerate to severe hypoxaemia and tachypnoea, high IL-6 and other inflammatory markers
May progress to types 4 or 5
4∼2/3 of patients needing mechanical ventilationSevere hypoxaemia requiring mechanical ventilation, normal lung compliance, good response to nitric oxide, prone position of little benefit, tidal volume >6 mL·kg−1 allowed, respiratory rate <20 beats·min−1, PEEP <10 cmH2O
5∼1/3 of patients needing mechanical ventilationHigh procalcitonin may be increased if mechanical ventilation is delayed in severely hypoxaemic patients, more in keeping with classical ARDS
Protective ventilatory strategy and prone position indicated

SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; IL-6: interleukin-6; PEEP: positive end-expiratory pressure; ARDS: acute respiratory distress syndrome.