Study Exclusion reasons Remarks Reference(s)
Rimland, 2020 single-arm  
BREATH-19 Study, 0 single-arm  
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