2.2 Clinical data collection and definitions
Electronic and written medical records were reviewed for all subjects.
Data collected included demographic details, comorbid illnesses,
presenting symptoms and signs, blood biochemical indexes, antiviral and
antibiotic use, vasoactive drugs received (dobutamine or noradrenaline),
intensive care unit (ICU) admission, hospital length of stay,
requirement for ventilatory support, and occurrence of adverse events.
Pneumonia was defined as the presence of pulmonary infiltrates on chest
imaging not contributable to other causes. ARDS was defined based on the
Berlin definition21. Immune deficiency was defined as
organ transplant, active therapy for malignancy, and high-dose
steroids/other iatrogenic drugs. Mixed infection of H1N1 and COVID-19 is
defined as nucleic acid detection show positivity in both viruses, and
the management measures refer to those of COVID-19 infection.