Statistically significant lower risk is seen for recovery and viral clearance. 30 studies from 30 independent teams in 16 countries show statistically significant improvements.
Meta analysis using the most serious outcome reported shows 15% [5‑24%] lower risk. Results are similar for Randomized Controlled Trials, higher quality studies, and peer-reviewed studies.
Studies to date show no significant difference for mortality. A small mortality improvement is seen, without statistical significance, however meta regression with followup duration shows decreasing efficacy with longer followup. There is also no benefit seen for mechanical ventilation, ICU admission, or hospitalization. This may reflect antiviral efficacy being offset by side effects of treatment.
1 RCT with 1,008 patients has not reported results (2 years late) Kara.
Potential risks of the mechanism of action include the creation of dangerous variants, and mutagenicity, carcinogenicity, teratogenicity, and embryotoxicity Hadj Hassine, Waters, Zhirnov. Favipiravir may impair clotting Gül.
No treatment or intervention is 100% effective. All practical, effective, and safe means should be used based on risk/benefit analysis. Multiple treatments are typically used in combination, and other treatments are significantly more effective.
All data to reproduce this paper and sources are in the appendix.
Covid Analysis et al., Mar 2024, preprint, 1 author.