• Statistically significant improvements are seen for mortality, hospitalization, progression, recovery, cases, and viral clearance. 19 studies from 13 independent teams in 4 different countries show statistically significant improvements in isolation (11 for the most serious outcome).
• Meta analysis using the most serious outcome reported shows 53% [33‑66%] improvement. Results are similar for Randomized Controlled Trials, similar after exclusions, and similar for peer-reviewed studies.
• Results are robust — in exclusion sensitivity analysis 12 of 26 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis.
• Efficacy is variant dependent.
In Vitro studies suggest a lack of efficacy for omicron [Liu, Sheward, Tatham, VanBlargan]. Monoclonal antibody use with variants can be associated with prolonged viral loads, clinical deterioration, and immune escape [Choudhary]. ADE shown
In Vitro [Shimizu].
• No treatment, vaccine, or intervention is 100% effective and available. 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. Only 27% of casirivimab/imdevimab studies show zero events with treatment.
• All data to reproduce this paper and sources are in the appendix.
Percentage improvement with casirivimab/imdevimab (more) | All studies | Early treatment | Prophylaxis | Studies | Patients | Authors |
All studies | 53% [33‑66%]**** | 47% [25‑62%]*** | 93% [79‑97%]**** | 26 | 54,453 | 386 |
Randomized Controlled TrialsRCTs | 61% [32‑78%]*** | 63% [42‑76%]**** | 93% [79‑97%]**** | 9 | 21,306 | 178 |
Mortality | 40% [1‑64%]* | 65% [-6‑88%] | - | 8 | 32,929 | 216 |
HospitalizationHosp. | 42% [17‑59%]** | 39% [9‑59%]* | 92% [-36‑100%] | 12 | 46,106 | 133 |
Cases | 80% [39‑93%]** | 33% [2‑57%] | 85% [74‑91%]**** | 4 | 3,265 | 71 |
Covid Analysis et al., Mar 2023, preprint, 1 author.