(P12-017-23) Effect of Vitamin D and Zinc Supplementation on Treatment Outcomes Among COVID-19 Patients in India: Results From a Double-Blind Randomized Placebo-Controlled Trial

Objectives: Previous evidence indicates the role of vitamin D and zinc in respiratory infections. We sought to understand the effect of vitamin D and zinc supplementation on treatment outcomes among individuals with mild-to-moderate COVID-19 in Mumbai and Pune, India.

Methods: We undertook a double-blind randomized placebo-controlled trial, with 2x2 factorial design and 1:1:1:1 allocation ratio. Non-pregnant adults (N=181) with COVID-19 were enrolled from hospitals, and were randomized to 8-week supplementation with vitamin D3 (180,000 IU bolus, then 2000 IU daily), zinc (40 mg daily), vitamin D3 and zinc, or placebo. Participants were followed daily in hospital and every three days after leaving the hospital to assess outcomes and other measures, until 8 weeks. The primary outcome was time to resolution of all of fever, cough, and shortness of breath. Secondary outcomes included duration of individual symptoms; duration of hospital stay; need for assisted ventilation; all-cause mortality; and levels of nutritional, inflammatory and immunological biomarkers.

Results: Neither vitamin D nor zinc supplementation was found to affect time to resolution of all three symptoms (vitamin D hazard ratio [HR]: 0.92, 95% confidence interval [95% CI]: 0.66-1.30, P=0.650; zinc HR: 0.94, 95% CI: 0.67-1.33, P=0.745). Similarly, we found no effect of either intervention on secondary outcomes, except for increased endline serum vitamin D levels among participants supplemented with vitamin D (median [interquartile range] difference between endline and baseline for vitamin D: 5.3 ng/mL [-2.3-13.7]; for no vitamin D: -1.4 ng/mL [-5.6-3.9]; P=0.003), and non-significant increased endline serum zinc levels among participants supplemented with zinc. We found no evidence of interaction between vitamin D and zinc supplementation, and no effect of either treatment on hypercalcemia. No adverse events were observed.

Conclusions: Our findings suggest that neither vitamin D nor zinc supplementation may improve treatment outcomes for mild-to-moderate COVID-19. Larger-scale evidence, particularly based in populations with baseline vitamin D or zinc deficiency and more severe infection, would be valuable.

Funding Sources: Canadian Institutes of Health Research, Canada Research Chairs Program, National Institutes of Health