May passive immunotherapy with Equine polyclonal antibodies (EpAbs) reduce ICU admission, mechanical ventilation requirement or death at day 28 of follow for patients with COVID-19? – An Update

Objective: To test whether selection bias has affected the reported effect estimate for Equine polyclonal antibodies (EpAbs) (Risk Difference, -0.07; 95%CI: -0.16 to 0.03; p = 0.16) to reduce ICU admission, mechanical ventilation requirement or death at day 28 of follow up. Method: Trial adjusted, simulated comparator trial (SCT) based I2 test for single randomised controlled trials, using revised I2 threshold limits. Result: A baseline covariate imbalance, either due to chance or due to selection bias was established, being equivalent to selection bias level = B% 0-30 (Bias category = 1). This level suggests that 0-39% of (0 – 94 of the total 241) subjects were non-randomly allocated in favour of one treatment group above the other. Conclusion: The effect estimate reported by the tested trial does not suggest any significant differences in ICU admission, mechanical ventilation requirement or death at day 28 of follow up for Equine polyclonal antibodies above the control intervention (placebo). The selection bias level, estimated by use of the trial adjusted, SCT based I2 test for single RCTs (B% = 0-30), appears to be low enough in order not to have affected the reported effect estimate. In line with new findings, this report updates previous report to the same RCT: EBSM Volume 2, Issue 1, 2026 Pages 1-4, DOI: 10.5281/zenodo.17760735.