We read with interest the article recently published by Catteau et al from the Belgian Collaborative group on COVID-19 Hospital surveillance reporting on a retrospective observational study of 8075 COVID-19 patients treated in 109 Belgian hospitals between March and May 2020. [...]
De Schryver, N., Serck, N., Vinetti, M., & Gérard, L. (2021). Low-dose hydroxychloroquine therapy and lower mortality in hospitalized patients with COVID-19: association does not mean causality. International Journal of Antimicrobial Agents, 57(1), 106254 [1-2]. https://doi.org/10.1016/j.ijantimicag.2020.106254 (Original work published 2021)