“…Three studies were prospective ( 24 , 30 , 36 ),14 were retrospective ( 22 , 23 , 25 – 29 , 31 , 33 , 34 , 37 – 40 ), whereas the remaining two did not explicitly state the study design ( 32 , 35 ). Disease severity, based on current clinical guidelines, was assessed in 11 studies ( 22 , 23 , 25 , 28 , 30 , 33 , 35 , 37 – 40 ), prolonged viral clearance in two ( 26 , 36 ), transfer to ICU in one ( 29 ), survival in three ( 27 , 31 , 32 ), presence of acute respiratory distress syndrome in one ( 34 ), and multiple end points in one ( 24 ).…”