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The Role of Zinc in Antiviral Immunity.


Zinc is an essential trace element that is crucial for growth, development, and the maintenance of immune function. Its influence reaches all organs and cell types, representing an integral component of approximately 10% of the human proteome, and encompassing hundreds of key enzymes and transcription factors. Zinc deficiency is strikingly common, affecting up to a quarter of the population in developing countries, but also affecting distinct populations in the developed world as a result of lifestyle, age, and disease-mediated factors. Consequently, zinc status is a critical factor that can influence antiviral immunity, particularly as zinc-deficient populations are often most at risk of acquiring viral infections such as HIV or hepatitis C virus. This review summarizes current basic science and clinical evidence examining zinc as a direct antiviral, as well as a stimulant of antiviral immunity. An abundance of evidence has accumulated over the past 50 y to demonstrate the antiviral activity of zinc against a variety of viruses, and via numerous mechanisms. The therapeutic use of zinc for viral infections such as herpes simplex virus and the common cold has stemmed from these findings; however, there remains much to be learned regarding the antiviral mechanisms and clinical benefit of zinc supplementation as a preventative and therapeutic treatment for viral infections.

 Zinc and the common cold

 The common cold is the primary cause of doctor visits in the United States, leading to 189 million lost school days each year. But itís important to point out that the common cold can be caused by a number of different viruses, including rhinovirus, coronavirus, influenza virus, adenovirus, and paramyxovirus. Rhinoviruses are responsible for over half of all common colds.

 The idea that zinc could be used to treat the common cold originated from a 1974 paper in Nature which showed that zinc blocks the replication of rhinoviruses in cell culture. Viral plaque formation was inhibited over 99% when 0.1 millimolar zinc chloride was included in the agar overlay. . . . . . . . . . Zinc does not readily pass through the cell membrane, explaining why high concentrations are required to produce an antiviral effect.