full title "No evidence of clinical efficacy of hydroxychloroquine in patients hospitalised for COVID-19 infection and requiring oxygen:..." from the article:

full title "No evidence of clinical efficacy of hydroxychloroquine in patients hospitalised for COVID-19 infection and requiring oxygen:..." from the article: "We used data collected from routine care of all adults in 4 French hospitals with documented SARS-CoV-2 pneumonia and requiring oxygen ≥ 2 L/min to emulate a target trial aimed at assessing the effectiveness of HCQ at 600 mg/day... This study included 181 patients with SARS-CoV-2 pneumonia; 84 received HCQ within 48 hours of admission (HCQ group) and 97 did not (no-HCQ group). The median age of patients was 60 years ..." "...[Patients were from] four French tertiary care centres providing care to patients with COVID-19 pneumonia. Adult patients were eligible in this study if they were aged between 18 years and 80 years, had PCR-confirmed SARS-CoV-2 infection, and required oxygen by mask or nasal prongs (corresponding to a WHO progression score of 5)." "Among the 181 patients eligible for analysis, 84 received HCQ within 48 hours of admission and 97 did not (although 8 of them did receive HCQ later on)." So, first of all, these patients were infected with Covid-19 _days_ prior and now had progressed to pneumonia. The up to two-day delay in the administration of HCQ after admittance to the study is disheartening. I am surprised that, despite the experimentors selecting an elderly, pneumonic, oxygen-dependent cohort in advanced stages of the disease, these patients did as well as they did. Its a credit to the human body. But timing is everything... Once a Covid-19 patient has developed pneumonia, it is too late for hydroxychloroquine to affect the Covid-19 virus' replication process significantly. The patient's body is saturated with the virus. In a patient who has developed pneumonia the disease has progressed to a second phase wherein the virus and other opportunistic pathogens (e.g., bacteria) attack the lungs and other tissue. Antibiotics may help at this point. But it is quite clear that the patients in this study arrived too late to gain any benefit from hydroxychloroquine which, when coupled with zinc sulfate, slows or halts viral replication _early_ in the disease, delays or halts the virus' progress and allows the body time to develop an immunological response to the virus. The study's conclusion states explicitly that " These results ... do not support the use of HCQ in patients hospitalised for a documented SARS-CoV-2 pneumonia." So, the trick is to treat _early_ with HCQ+zinc sulfate+azithromycin.