Antihistamine H1RAs reduce COVID-19 risk: real-time meta-analysis of 17 studies (Version 16)

Significantly lower risk is seen for mortality, recovery, cases, and viral clearance. 10 studies from 8 independent teams in 6 countries show significant benefit.

Meta-analysis using the most serious outcome reported shows 37% [22‑50%] lower risk. Results are similar for Randomized Controlled Trials and peer-reviewed studies. Early treatment is more effective than late treatment.

Results are very robust—in worst case exclusion sensitivity analysis 9 of 17 studies must be excluded before statistical significance is lost. Emergent results for meta-regression of efficacy vs. treatment delay (p = 0.00074) that match biological mechanisms confirm efficacy.

Control Antihistamine H1RAsH1RAs

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.