Unfortunately the researchers did not test patients for B12 deficiency (using B12, MMA and/or Hcy) prior to the study to see what percent of patients had undiagnosed metabolic B12 deficiency. Next, they gave B12 with another vitamin (vitamin D) and a mineral (magnesium). I disagree with giving all three as a cocktail without study arms investigating each one individually. It would have been a better study to have 4 groups, one group for each treatment, and a 4th group containing all three. However, this study supports the use of B12 in COVID-19.