Table 2.
Summary of findings from studies that included zinc supplementation in the COVID-19 treatment.
| References | Study design, setting, gender, age | Therapy, regimen | N, severity of COVID-19, and comorbidities | Outcomes |
|---|---|---|---|---|
| Patel et al. (36) | RCT; Hospital; Male (64.4%); 61.8 ± 0.1 years. | •Group 1 (N = 15): 0.5 mg/kg/day of intravenous zinc chloride for a maximum of 7 days. •Group 2 (N = 18): saline placebo. |
N = 33; Severity of COVID-19: NR. Comorbidity: hypertension (48.3%), DM (18.3%), cardiovascular (21.7%) and respiratory (11.1%) disease, cirrhosis (16.7%), hepatic failure (5.6%). | •↑ [serum zinc levels] in the intervention group, above the deficiency cutoff [10.7 μmol/l] 6 days after the supplementation, while the placebo group stayed below the cutoff. |
| Thomas et al. (37) | RCT; Ambulatory; Female (61.7%); 45.2± 14.6 years. | •Group 1 (N = 48): 8000 mg of VC (10 days). •Group 2 (N = 58): 50 mg of zinc gluconate (10 days). •Group 3 (N = 58): a combination of both therapies in groups 1 and 2 (10 days). •Group 4 (N = 50): no supplementation (ST). |
N = 214; Moderate and Severe COVID-19; Comorbidity: DM (13.6%), hypertension (32.7%), dyslipidemia (26.2%), asthma (15.4%), anxiety (18.2%), depression (15.4%). | •Days required to reach 50% reduction in symptoms: No difference among the groups. •No distinction in the number of days to reach no presence of cough, fever, shortness of breath, or fatigue among the groups. |
| Abdelmaksoud et al. (38) | RCT; Hospital; Male (58.2%); 52.0 ± 12.2years. | •Group 1 (N = 49): 220 mg zinc sulfate equivocal to 50 mg elemental twice daily until complete recovery of COVID-19. •Group 2 (N = 56): no supplementation (ST). |
N = 134; Mild, common, severe, and extremely severe COVID-19; Comorbidity: DM (16.1%), hypertension (11.7%), ischemic heart disease (6.1%). | •Duration of smell recovery: ↓ zinc group compared to CG. •Total recovery duration of COVID-19: no difference. |
COVID-19, coronavirus disease 2019; CG, control group; NR, not reported; mg: DM, diabetes mellitus; mg, milligram; kg, kilogram; μmol/l, micromole per liter; VC, vitamin C; ST, standard therapy; ↑, increase; ↓, decrease.