The efficacy and adverse effects of favipiravir on patients with COVID-19: A systematic review and meta-analysis of published clinical trials and observational studies

Objectives: This study aimed to evaluate the efficacy and adverse events of favipiravir in patients with COVID-19. Methods: Our protocol was registered on PROSPERO (CRD42020206305). Fourteen databases were searched until February 8th, 2021. An update search for new RCTs was done on March 2nd, 2022. Meta-analysis was done for randomized controlled trials (RCTs) and non-RCTs. Results: Overall, 157 studies (24 RCTs, 1 non-RCT, 21 observational studies, 2 case series, and 106 case reports) were included. On hospitalized patients, in comparison to standard of care, favipiravir showed a higher rate of viral clearance at day 5 (RR = 1.60, p = 0.02), defervescence at day 3–4 (RR = 1.99, p