Tocilizumab and COVID-19: Timing of administration assessment

•Recent evidence showed efficacy of tocilizumab in COVID-19 patients.•The efficacy of tocilizumab was greater in the subgroup of oxygen-dependent patients, only and if injected within 7 days following symptom onset.•This subgroup was highly heterogeneous and precise timing for tocilizumab injection according to the oxygen level remains to be determined.•We showed no association between timing of injection after symptom onset and the efficacy of tocilizumab on the mortality rate.•In a secondary exploratory analysis, our study suggested that tocilizumab could be less effective when oxygen requirement is >11L/min compared to an earlier administration.•However, this hypothesis remains to be verified by administration timing-related randomized clinical trials.