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 < 0.01), chest radiological improvement (RR = 1.33, p < 0.01), hospital discharge at day 10-11 (RR = 1.19, p < 0.01), and shorter clinical improvement time (MD = -1.18, p = 0.05). Regarding adverse events, favipiravir groups had higher rates of hyperuricemia (RR = 9.42, p < 0.01), increased alanine aminotransferase (RR = 1.35, p < 0.01) but lower rates of nausea (RR = 0.42, p < 0.01) and vomiting (R R = 0.19, p = 0.02). There were no differences regarding mortality (RR = 1.19, p = 0.32), and increased aspartate aminotransferase (RR = 1.11, p = 0.25). On nonhospitalized patients, no significant differences were reported. Conclusions: Adding favipiravir to the standard of care provides better outcomes for hospitalized patients with COVID-19. Pregnant, lactating women, and patients with a history of hyperuricemia should avoid using favipiravir.(C) 2022 Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

Favipiravir has shown better outcomes for hospitalized COVID-19 patients, with improved viral clearance, defervescence, chest radiological improvement, hospital discharge rates, and shorter clinical improvement time. However, there are some adverse events associated with its use. No significant differences were observed in non-hospitalized patients.