Zinc as an adjunct treatment for COVID-19 patients

ABSTRACT

Objective@#To present the current evidence on the effect of zinc as adjunct therapy on COVID-19 related outcomes. @*Methods@#A literature search among peer-reviewed, non-peer-reviewed, and guideline practice databases was done until December 26, 2020, with an updated search done on February 13, 2021. Evidence was synthesized among studies that fulfilled the inclusion criteria, and the quality of evidence was determined using GRADEpro.@*Results@#This review used two randomized controlled trials and three retrospective cohort studies. Pooling of the retrospective cohort studies showed that adjunct zinc therapy significantly reduces the risk of mortality or transition to hospice care among COVID-19 patients (OR 0.56, 95% CI 0.38-0.81; I2=p=0.002; very low quality of evidence). However this was not supported by one RCT (N=191) which showed no significant difference in death (RR 0.99, 95% CI, 0.30-3.31; p=0.99], need for mechanical ventilation (RR 0.66, 96% CI, 0.19-2.26; p=0.58] and recovery after 28 days (RR 0.94, 95% CI 0.55-1.62; p=0.83) in patients with COVID-19 given zinc as adjunct treatment together with hydroxychloroquine (HCQ) and azithromycin (AZT) versus HCQ and AZT alone (moderate quality of evidence). A second RCT (N=108) showed no significant difference in the hospitalizations (RR 1.44, 95% CI 0.36, 5.71; p=0.61) and meant several days needed to reach a 50% reduction in symptoms in ambulatory patients with COVID-19 given adjunct zinc gluconate versus standard of care alone (mean difference of -0.80, 95% CI, -2.55-0.95, p=0.37; low quality of evidence). In this study, there were 10 participants in the zinc group with adverse effects, mostly gastrointestinal in origin. @*Conclusion@#There is still insufficient evidence to support the use of Zinc as an adjunct therapy in patients with COVID-19 both in inpatient and outpatient settings due to inconsistent benefits and potential adverse effects.