IL18 and COVID-19: The major functions of vitamin D3 are inhibiting the proinflammatory pathways, including nuclear factor kappa B (NF-kB), inflammatory cytokines, such as interleukin-6 (ILs-6), interleukin-18 (ILs-18), and tumour necrosis factor (TNF), preventing the loss of neural sensation in COVID-19, maintaining respiratory homeostasis, and acting as an antiviral, antimalarial, and antihypertensive agent.