Four studies from the University of Oxford, the American Society for Microbiology, the U.S. National Library of Medicine, and PLOS Pathogen outline the antiviral effects of zinc in the human body, including the immune system and respiratory system, and its efficacy against the common cold and coronavirus.

From Oxford Academic:

The Role of Zinc in Antiviral Immunity

ABSTRACT

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.

Clinical studies using zinc supplementation are primarily limited to rhinovirus infection, and are often grouped with other “common cold” viruses such as influenza and coronaviruses.

The majority of studies use zinc lozenges with various zinc formulations and concentrations, possibly explaining the large variability in results [extensively reviewed in (108) and (109)].

Importantly, the amount of ionic zinc present at the site of infection (oral and nasal mucosa) is highly correlated to the study outcome (51, 108), and is dependent on the zinc formulation.

At a physiological pH and 37°C, zinc gluconate for example, releases high amounts of ionic zinc, whereas zinc aspartate releases none (108).

Upon examining only the relevant studies where high doses of ionic zinc were used, a clear reduction in cold duration of 42% was calculated (109).

Whether this was caused by viral inhibition, improved local immune response, or an amelioration of symptoms remains uncertain.

Other respiratory tract infections: influenza, coronavirus, and metapneumovirus – Continue reading on Oxford Academic.

Zn2+ Inhibits Coronavirus and Arterivirus RNA Polymerase Activity In Vitro and Zinc Ionophores Block the Replication of These Viruses in Cell Culture – Continue reading on PLOS Pathogens.

Effect of Zinc Salts on Respiratory Syncytial Virus Replication – Continue reading on American Society for Microbiology.

Efficacy of Zinc Against Common Cold Viruses: An Overview – Continue reading on the U.S. National Library of Medicine.

Excerpts of THIS much larger article.