Meta analysis using the most serious outcome reported shows 34% [-24‑65%] lower risk, without reaching statistical significance. Results are similar for peer-reviewed studies and worse for Randomized Controlled Trials. 2 studies from 2 independent teams (both from the same country) show significant benefit.
Currently there is limited data, with only 34 control events for the most serious outcome in trials to date.
Efficacy is variant dependent. In Vitro research suggests a lack of efficacy for omicron BQ.1.11, BA.5, BA.2.75, XBB, XBB.1.5, XMM.1.9.12,3. mAb use may create new variants that spread globally4,5, and may be associated with prolonged viral loads, clinical deterioration, and immune escape5-8.
Prescription treatments have been preferentially used by patients at lower risk9. 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 is 100% effective. Protocols combine safe and effective options with individual risk/benefit analysis and monitoring. Other treatments are more effective. All data and sources to reproduce this analysis are in the appendix.
Covid Analysis et al., Mar 2025, preprint, 1 author.
