Dietary Supplements for COVID-19

This study proposed is a double-blind, placebo-controlled, phase III randomized controlled trial powered to detect meaningful differences in the overall health and symptom severity of people with COVID-19 between the treatment and control arms. Eligible participants will be randomly assigned, using a web randomization system, in a ratio of 1:1 to one of the following groups: (1) nutrient therapy with vitamin D, vitamin C, vitamin K2, and zinc or (2) placebo. Total trial duration will be 12 weeks. Nutrients or placebo will be given for a period of 21 days following enrolment and randomization. Total trial duration will be 12 weeks. Adverse events will be collected during the treatment phase plus one additional week (maximum 4 weeks). With respect to the primary outcome of participant-reported overall health, power calculations were conducted based on between-group differences at a single time point (21 days) and Cohen's guideline for a small effect size of 0.3. A sample size of 176 (88 per arm) provides 80% power to detect a difference at an α of 0.05. To account for an approximate 10-15% lost to follow-up we will enrol 200 participants (100 per arm).