HCQ is not effective when used very late with high dosages over a long period (RECOVERY/SOLIDARITY), effectiveness improves with earlier usage and improved dosing. Early treatment consistently shows positive effects. Negative evaluations typically ignore treatment time, often focusing on a subset of late stage studies.
(hydroxychloroquine) Database of all hydroxychloroquine COVID-19 studies. Updated 12 March 2021. https://hcqmeta.com.