To the Editor,
I read the article by Mohammad Bosaeed and colleagues [1] with great interest. This randomized controlled trial of mild COVID-19 patients found no evidence that favipiravir did not reduce the time to clearance within 15 days of starting the treatment in the modified intention-to-treat analysis. Since most COVID-19 cases would not progress to severe illness or require hospitalization, viral clearance was used as the primary outcome in this study. However, I think that an additional per-protocol analysis may be important because intention-to-treat analysis may underestimate the effect of favipiravir. Relatedly, the authors did not show the viral load at randomization. I am concerned that variation in baseline viral load may affect the results of viral clearance. Finally, in Saudi Arabia, vaccination began in January 2021. During this period, there was the alpha strain epidemic for which the vaccine was effective, and I believe that the results may be affected by the presence or absence of vaccination, so we propose to add this to the limitations.
Transparency declaration
Nobuaki Mori has no conflicts of interest to declare. No funding was received.
Editor: L Leibovici
Reference
- 1.Bosaeed M., Alharbi1 A., Mahmoud E., Alrehily S., Bahlaq M., Gaifer Z., et al. Efficacy of favipiravir in adults with mild COVID-19: a randomized, double-blind, multicentre, placebo-controlled clinical trial. Clin Microbiol Infect. 2022;28:602–608. doi: 10.1016/j.cmi.2021.12.026. [DOI] [PMC free article] [PubMed] [Google Scholar]