Press Room: June 3

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By Bernd Sebastian Kamps
& Christian Hoffmann

3 June

Hydroxychloroquine – no better than placebo

On 22 May, a study by Mehra et al. published in The Lancet seemed to sound the death bell of hydroxychloroquine. In a truly “extraordinary” multinational registry analysis from “671 hospitals on six continents”, 14,888 patients (1,868 received CQ; 3,783 received CQ with azithromycin or clarithromycin; 3,016 received HCQ; and 6,221 received HCQ with a macrolide) were compared to 81,144 control patients who did not receive these drugs. Mortality was reported to be higher in all treatment groups than in the controls (18.0-23.8% versus 9.3%), etc., etc.

Alas, only days later Guardian Australia revealed errors in the Australian data included in the study (see The Guardian, 28 May 2020). The study is now disputed by 120 physicians and researchers who scrutinized in detail the publication (see (Watson 2020: PDF + Web page). In addition to the scientific questions, members of the scientific community wonder how a small Illinois-based company could collect more than 96,000 medical records “from 671 hospitals on six continents” and have the capacity to maintain relations with such a large number of hospitals around the world.

On 3 June, The Lancet published a short expression of concern: “Important scientific questions have been raised about data reported in the paper by Mandeep Mehra et al. (…) Although an independent audit of the provenance and validity of the data has been commissioned by the authors not affiliated with Surgisphere and is ongoing, with results expected very shortly, we are issuing an Expression of Concern to alert readers to the fact that serious scientific questions have been brought to our attention. We will update this notice as soon as we have further information.”

Are these developments good news for hydroxychloroquine? Probably not, because at least six other studies were unfavorable to the drug (see our Top 10 Special, 25 May). What’s more, on June 3, the New England Journal of Medicine published the results of a randomised, controlled trial which tested hydroxychloroquine as postexposure prophylaxis. The results: After high-risk or moderate-risk exposure to Covid-19, hydroxychloroquine did not prevent illness compatible with Covid-19 or confirmed infection when used as postexposure prophylaxis within 4 days after exposure (Boulware 2020).

International Press Room

28 May, The Guardian: Questions raised over hydroxychloroquine study which caused WHO to halt trials for Covid-19

29 May, The Guardian: Covid-19 study on hydroxychloroquine use questioned by 120 researchers and medical professionals

3 June, The Guardian: Governments and WHO changed Covid-19 policy based on suspect data from tiny US company

3 June, The Guardian: How were medical journals and WHO caught out over hydroxychloroquine?

3 June, Le Monde: Hydroxychloroquine : « The Lancet » met en garde contre une étude publiée dans ses colonnes

3 June, Le Monde : L’OMS reprend ses essais sur l’hydroxychloroquine comme traitement potentiel contre le coronavirus

3 June, El País: La OMS reinicia los ensayos en pacientes con hidroxicloroquina

3 June, Süddeutsche Zeitung: Wurden Tests mit Malaria-Medikament zu Unrecht gestoppt?

3 June, Corriere della sera: Coronavirus, «lo studio che ha affossato l’idrossiclorochina è basato su dati sospetti».

3 June, The Guardian: Hydroxychloroquine no better than placebo, Covid-19 study finds


Mehra MR, Desai SS, Ruschitzka F, Patel AM. Hydroxychloroquine or chloroquine with or without a macrolide for treatment of COVID-19: a multinational registry analysis. Lancet 2020, May 22. Full-text:

Watson J, Adler, A, Amaravadi R, et al: Open letter to MR Mehra, SS Desai, F Ruschitzka, and AN Patel, authors of “Hydroxychloroquine or chloroquine with or without a macrolide for treatment of COVID-19: a multinational registry analysis”. May 28. Web:

Boulware DR, Pullen MF, Bangdiwala AS, et al. A Randomized Trial of Hydroxychloroquine as Postexposure Prophylaxis for Covid-19. N Engl J Med 2020, June 3. Full-text: