Upregulates ACE2 expression, decreases lethality of COVID‐19 at a dosage of 50,000 IU weekly. Increases RIG‐1/MDA‐5 and JAK–STAT signaling pathways. Calcitriol can impede replication of SARS‐CoV‐2 in vitro. The gene discussed is ACE2; the disease is COVID-19.