The effect of zinc supplementation on the course of COVID-19 - A systematic review and meta-analysis

Introduction and objective: Zinc is a trace element that plays a role in stimulating innate and acquired immunity. The aim of the study was to determine the antiviral effect of the administration of zinc in COVID-19 patients.

Material and methods: A literature search was performed in P Web of Science, PubMed, Scopus and Cochrane databases from 1 January 2020 - 22 August 2022. In addition, reference lists of the included articles and their related citations in PubMed were also reviewed for additional pertinent studies.

Results: A total of 9 eligible studies were identified. In-hospital mortality in zinc supplementation patients, and patients treated without zinc, varied and amounted to 21.6% vs. 23.04% difference (OR=0.71; 95%CI: 0.62-0.81; p<0.001). 28-day to 30-day mortality in patients treated with zinc was 7.7%, compared to 11.9% for patients treated without zinc (OR=0.61; 95%CI: 0.35-1.06; p=0.08). In-hospital adverse events among patients treated with and without COVID-19 did not show any statistically significant differences in relation to acute kidney injury occurrence (12.8% vs. 12.4%, respectively; OR=0.63; 95%CI: 0.19-2.12; p=0.45, as well as need for mechanical ventilation (13.2% vs. 14.1%; OR=0.83; 95%CI: 0.52-1.32; p=0.43).

Conclusions: Zinc supplementation is associated with lower COVID-19 in-hospital mortality. Additionally, it is risk-free in COVID-19 patients since there have been no negative side effects, such as acute renal damage or the requirement for mechanical ventilation compared to patients without COVID-19. Due to scientific evidence and the role it represents in the human body, zinc supplementation should be taken into consideration for COVID-19 patients as an adjunct therapy.