Study		Exclusion reasons	Remarks	Reference(s)
Rimland, 2020	single-arm
BREATH-19 Study, 0	single-arm
Gritti et al., 2020	single-arm	inadequate or absent control group		Gritti et al. medRxiv 10.1101/2020.04.01.20048561
Toniati, 2020	observational study	no control group		Toniati Autoimmun Rev 2020; 19:102568 10.1016/j.autrev.2020.102568
Price, 2020	retrospective cohort	no control group		Price Chest 2020; : 10.1016/j.chest.2020.06.006
Holt, 2020	retrospective cohort	other	no CI reported	Holt, Gregory E 10.21203/rs.3.rs-39875/v1
Klopfenstein, 2020	retrospective cohort	other	major flaws in the method	Klopfenstein T International Journal of Infectious Diseases 10.1016/j.ijid.2020.08.024