Evidently Tacrolimus is a prophylactic for Covid 19 in preventing sever infection.
Tacrolimus is immunosuppressive by inhibiting calcineurin, and suppressing the early phase of T-cell activation, and the expression of many cytokines (IL-2, IL-4, TNF-α and IFN-γ) that are needed in the activation of the cellular immune response, possibly preventing a cytokine storm as observed in severe COVID-19.Jun 27, 2020
https://www.ncbi.nlm.nih.gov › pmc
Calcineurin inhibitors revisited: A new paradigm for COVID-19? - NCBI - NIH