inclusion criteria: * age ≥ 18 years old * tested positive for sars-cov-2 using real-time reverse transcriptase pcr (rt-pcr) nasopharyngeal swabs * clinical signs of acute respiratory infection and radiological evidence of pneumonia * hospital admission in any ward or emergency department within 48 h * spo2 ≤ 92% or pao2/fio2 \< 300 in room air and need for oxygen therapy according to clinical judgment, at the screening.

inclusion criteria: * age ≥ 18 years old * tested positive for sars-cov-2 using real-time reverse transcriptase pcr (rt-pcr) nasopharyngeal swabs * clinical signs of acute respiratory infection and radiological evidence of pneumonia * hospital admission in any ward or emergency department within 48 h * spo2 ≤ 92% or pao2/fio2 \< 300 in room air and need for oxygen therapy according to clinical judgment, at the screening.

inclusion criteria: - age ≥ 18 years old - tested positive for sars-cov-2 using real-time reverse transcriptase pcr (rt-pcr) nasopharyngeal swabs - clinical signs of acute respiratory infection and radiological evidence of pneumonia - hospital admission in any ward or emergency department within 48 h - spo2 ≤ 92% or pao2/fio2 < 300 in room air and need for oxygen therapy according to clinical judgment, at the screening.

inclusion criteria: - age ≥ 18 years old - tested positive for sars-cov-2 using real-time reverse transcriptase pcr (rt-pcr) nasopharyngeal swabs - clinical signs of acute respiratory infection and radiological evidence of pneumonia - hospital admission in any ward or emergency department within 48 h - spo2 ≤ 92% or pao2/fio2 < 300 in room air and need for oxygen therapy according to clinical judgment, at the screening.