Zinc is a trace element in human body. An element is called as trace elements when their requirement per day is below 100 mg and deficiency leads to disorders and may prove fatal. The elements belonging to this group are copper, iron, zinc, chromium, cobalt, iodine, molybdenum, and selenium.
Zinc plays a vital role in the normal immune system in human body. Zinc inhibits secretion of cytokinin by modifying monocyte signal transduction and suppresses inflammation by interfering with the binding of leukocyte function-associated antigen-1 to ICAM-1.
Zinc supplementation has been shown its effectiveness in prophylaxis against respiratory viral infection. 30% of common respiratory infection, i.e. common cold is due to coronaviruses (1). Zinc supplementation in the form of Zinc lozenges was found to reduce symptom severity, frequency of episode and duration of common cold (2). Zinc supplementation was found to reduce pneumonia-related morbidly and mortality by 19% and 15% respectively (3).
There is so far no scientific study suggesting the role of zinc supplementation as prophylaxis against Covid-19. There are some assumptions and extrapolations: