COVID-19 Evidence Alerts
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Current best evidence for clinical care (more info)

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Treatment Manabe T, Kambayashi D, Akatsu H, et al. Favipiravir for the treatment of patients with COVID-19: a systematic review and meta-analysis. BMC Infect Dis. 2021 May 27;21(1):489. doi: 10.1186/s12879-021-06164-x.
Abstract

BACKGROUND: Favipiravir possesses high utility for treating patients with COVID-19. However, research examining the efficacy and safety of favipiravir for patients with COVID-19 is limited.

METHODS: We conducted a systematic review of published studies reporting the efficacy of favipiravir against COVID-19. Two investigators independently searched PubMed, the Cochrane Database of Systematic Reviews, MedRxiv, and ClinicalTrials.gov (inception to September 2020) to identify eligible studies. A meta-analysis was performed to measure viral clearance and clinical improvement as the primary outcomes.

RESULTS: Among 11 eligible studies, 5 included a comparator group. Comparing to the comparator group, the favipiravir group exhibited significantly better viral clearance on day 7 after the initiation of treatment (odds ratio [OR] = 2.49, 95% confidence interval [CI] = 1.19-5.22), whereas no difference was noted on day 14 (OR = 2.19, 95% CI = 0.69-6.95). Although clinical improvement was significantly better in the favipiravir group on both days 7 and 14, the improvement was better on day 14 (OR = 3.03, 95% CI = 1.17-7.80) than on day 7 (OR = 1.60, 95% CI = 1.03-2.49). The estimated proportions of patients with viral clearance in the favipiravir arm on days 7 and 14 were 65.42 and 88.9%, respectively, versus 43.42 and 78.79%, respectively, in the comparator group. The estimated proportions of patients with clinical improvement on days 7 and 14 in the favipiravir group were 54.33 and 84.63%, respectively, compared with 34.40 and 65.77%, respectively, in the comparator group.

CONCLUSIONS: Favipiravir induces viral clearance by 7 days and contributes to clinical improvement within 14 days. The results indicated that favipiravir has strong possibility for treating COVID-19, especially in patients with mild-to-moderate illness. Additional well-designed studies, including examinations of the dose and duration of treatment, are crucial for reaching definitive conclusions.

Ratings
Discipline / Specialty Area Score
Emergency Medicine
Hospital Doctor/Hospitalists
Internal Medicine
Infectious Disease
Comments from MORE raters

Emergency Medicine rater

Very non-convincing meta-analysis of the clinical effect of favipiravir for COVID-19. All included studies were quite small. Viral clearance is an unimportant endpoint. For "clinical improvement" at day 7 or 14, only one RCT was included in the meta-analysis and did not show a difference. So, the suggestion of benefit was more driven by a couple of low-quality observational studies.

Emergency Medicine rater

As an internist working at a COVID-19 clinic, I found this article very useful!

Hospital Doctor/Hospitalists rater

This is a very timely study with evolving evidence and identifying potential treatments for Covid-19. I am also interested to see whether it has any difference in viral clearance with variants. As the authors identified, we need better studies to confirm, but so far it looks promising in patients with moderate disease.

Infectious Disease rater

This paper summarized the evidence for benefit from favipiravir in COVID-19 infection, which looks promising. The review covers only up to September 2020, so there may be more trials by now that might further clarify its usefulness.