Should zinc be used for COVID-19 prophylaxis or treatment? A rapid review [version 1; peer review: awaiting peer review]
Oghenekome A, Gbinigie and Ralph K. Akyea
Background: There have been intensive efforts worldwide to establish effective treatments for coronavirus disease 2019 (COVID-19), with recent interest in the use of zinc as a potential therapeutic agent. The aim of this rapid review was therefore to critically appraise and evaluate the evidence for using zinc as prophylaxis and/or treatment for COVID-19. Methods: We conducted electronic searches on 20th and 21st May 2020 of PubMed, TRIP, EPPI COVID Living Map, MedRxiv, Google Scholar and Google. All searches were updated on 11th July 2020 to check for new relevant studies. We included in vivo studies assessing the safety and effectiveness of zinc, alone or combined with other interventions, as treatment or prophylaxis for COVID-19. Studies assessing the activity of zinc against SARS-CoV-2 in vitro were also included. Results: We identified one observational study with a high risk of bias that was suitable for inclusion. The study authors found that treatment with a combination of zinc, azithromycin and hydroxychloroquine in patients hospitalised with COVID-19 resulted in increased odds of being discharged home (adjusted odds ratio (OR) 1.53; 95% CI 1.12 to 2.09; p = 0.008) and reduced odds of death or being transferred to a hospice (adjusted OR 0.559; 95% CI 0.385 to 0.811; p = 0.002), compared with treatment with hydroxychloroquine and azithromycin. Conclusions: We identified extremely limited evidence from a study with methodological problems of an association between improvement in certain outcomes when COVID-19 patients are treated with a combination of zinc, hydroxychloroquine and azithromycin, compared with treatment with hydroxychloroquine and azithromycin. The results of randomised clinical trials in this area should provide robust evidence of the effectiveness of zinc as treatment/prophylaxis for COVID-19.