Study 12 — The COVID-19 Dexamethasone Programme as Real-World Validation of Corticosteroid-Strongyloides Risk

Study 12 of the Hidden Infections research series. Evidence tier: STRONG. The RECOVERY trial established dexamethasone as standard of care for severe COVID-19. Mass dexamethasone deployment in Strongyloides-endemic regions of sub-Saharan Africa, South/Southeast Asia, and Latin America constituted an inadvertent real-world pharmacovigilance experiment for the corticosteroid-Strongyloides hyperinfection risk documented in Study 10. This study models the expected Strongyloides hyperinfection deaths during the COVID dexamethasone programme based on endemic prevalence, dexamethasone administration rates, and published case fatality rates. Key finding: Estimated 13,500-191,000 Strongyloides hyperinfection deaths occurred during the COVID dexamethasone programme, against 22 published case reports — a detection fraction of approximately 0.01-0.16%. The institutional response was editorials and a WHO Technical Brief that did not produce guideline change. Group C: Pharmacovigilance and surveillance. CC0 public domain. AI-assisted draft pre-print. | v3 correction (2026-09-18): fixed a mortality-figure misattribution — a reference note had cited '70-89% per Buonfrate 2013' for Strongyloides hyperinfection/disseminated disease case fatality; the actual Buonfrate et al. 2013 figures are 60% (hyperinfection) and 68.5% (disseminated disease), 62.7% overall (153/244 deaths). Corrected throughout this deposit's paper and reproducibility package.