March 24, 2021
Reviewed by Erica Kaufman West, MD
While some inpatient COVID-19 therapies have started emerging, an effective non-infusion outpatient treatment has not been discovered. Zinc gluconate and ascorbic acid supplements are available over the counter and have generated a lot of interest because of their purported roles in boosting the host’s immune response.
In a recent JAMA Network Open article, researchers reported the results of a randomized open-label clinical trial with a 1:1:1:1 randomization with 214 people receiving either 10 days of high-dose ascorbic acid (8,000 mg), zinc gluconate (50 mg), both, or neither. The primary end point was the number of days required to reach a 50% reduction in symptoms on a standardized scale. Only 214 patients of the planned 520 patients were enrolled; the interim analysis (at 40% enrollment) showed futility, so the rest of the trial was halted.
The mean days to achieve a 50% reduction in symptoms was 6.7 days in the usual care arm, 5.5 days in the ascorbic acid arm, 5.9 days in the zinc gluconate arm, and 5.5 days in the combined arm. While no drug-related adverse events were noted, there was no benefit shown either. An easy, effective outpatient treatment remains elusive, and prevention, including masks and social distancing, still seems to be the best medicine.