Vitamin C of little benefit to prevent or treat COVID-19, pneumonia

A recent Mendelian randomization study has found sparse evidence supporting the association of circulating vitamin C levels with the coronavirus disease 2019 (COVID-19) or pneumonia.

Drawing from a previous genome-wide association study of more than 50,000 people of European descent, the researchers evaluated nine single-nucleotide polymorphisms (SNPs) that were known to correlate with plasma concentrations of vitamin C. They then looked at the association between these SNPs and pneumonia incidence, as well as three COVID-19-related outcomes (severe disease, hospitalization, and laboratory-confirmed infection).

Analysis revealed that genetically predicted circulating levels of vitamin C was unrelated both with pneumonia (odds ratio [OR], 1.03, 95 percent confidence interval [CI], 0.91–1.71; p=0.61) and COVID-19 (OR, 1.04, 95 percent CI, 0.93–1.15; p=0.51) infection.

Moreover, vitamin C levels were not associated with the occurrence of severe COVID-19 (OR, 1.00, 95 percent CI, 0.74–1.35; p=0.995) or with the need to be hospitalized for the disease (OR, 1.10, 95 percent CI, 0.90–1.35; p=0.35).

“Despite decades of research, the therapeutic role of high-dose vitamin C infusion in critically ill patients, including those with severe pneumonia, is still not clear,” the researchers said.

“Our findings provided little evidence that normal vitamin C levels play a role in susceptibility to COVID-19 and pneumonia and thus does not support the use of normal-dose vitamin C for the prevention and treatment of COVID-19 infection or pneumonia,” they added.