Statistically significant lower risk is seen for mortality, hospitalization, recovery, cases, and viral clearance. 14 studies from 12 independent teams (all from the same country) show statistically significant improvements.
Meta analysis using the most serious outcome reported shows 49% [26‑64%] lower risk. Results are similar for higher quality and peer-reviewed studies and slightly worse for Randomized Controlled Trials. Results are consistent with early treatment being more effective than late treatment.
Results are robust — in exclusion sensitivity analysis 8 of 19 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis.
Efficacy is highly variant dependent. In Vitro studies suggest a lack of efficacy for omicron Haars, Liu, Pochtovyi, Sheward, VanBlargan. mAb use may create new variants that spread globally Focosi, Leducq, and may be associated with prolonged viral loads, clinical deterioration, and immune escape Choudhary, Günther, Leducq.
Prescription treatments have been preferentially used by patients at lower risk Wilcock. Retrospective studies may overestimate efficacy, for example patients with greater knowledge of effective treatments may be more likely to access prescription treatments but result in confounding because they are also more likely to use known beneficial non-prescription treatments.
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 may be more effective.
All data to reproduce this paper and sources are in the appendix.
Covid Analysis et al., Apr 2024, preprint, 1 author.
