A widely cited study about the use of Hydroxychloroquine and azithromycin to treat COVID-19, published in March 2020, has been retracted by its publisher, Elsevier.

The study, published in Elsevier’s International Journal of Antimicrobial Agents, was retracted in the January 2025 edition of the journal (issued last month).

“Concerns have been raised regarding this article, the substance of which relate to the articles’ adherence to Elsevier’s publishing ethics policies and the appropriate conduct of research involving human participants, as well as concerns raised by three of the authors themselves regarding the article’s methodology and conclusions,” the publisher notes.

The study involved 20 French patients, some of whom were given the antimalarial medicine Hydroxychloroquine. Six were also given the anti-bacterial drug, azithromycin.

“Untreated patients from another center and cases refusing the protocol were included as negative controls,” according to the study.

Patients treated with hydroxychloroquine were recruited and managed in the Méditerranée Infection University Hospital Institute in Marseille Marseille centre. Control patients were recruited in Marseille, Nice, Avignon and Briançon centers, all in South France.

Ethical questions

But the patients were recruited to the”open label non-randomised trial” in “early March” – possibly before ethical approval for the trial was given on 5-6th of that month.

In addition, the journal has been unable to establish whether “all patients could have entered into the study in time for the data to have been analysed and included in the manuscript prior to its submission”.

There are also questions about whether informed consent was obtained from the patients, lack of clarity about whether all patients were enrolled in the study upon admission to hospital or if they had been hospitalised for some time and whether there was sufficient “equipoise” between the study patients and the control patients.

None of the control patients are reported to have received azithromycin. At the time of the study, azithromycin was not used as first-line prophylaxis against pneumonia in France “due to the frequency of macrolide resistance amongst bacteria such as pneumococci.”, according to Elsevier. For that reason, informed consent would have been necessary to use it.

Author disputes

Three of the authors, Dr Johan Courjon, Prof Valérie Giordanengo, and Dr Stéphane Honoré, contacted the journal with concerns “regarding the presentation and interpretation of results in this article and have stated they no longer wish to see their names associated with the article”, Elsevier reported.

Giordanengo was concerned with analysis bias, raising that PCR tests administered in Nice were interpreted according to the recommendations of the national reference center,while those carried out in Marseille “were not conducted using the same technique or not interpreted according to the same recommendations”. 

The corresponding author, Didier Raoult, did not respond to the deadline to address concerns.

However, first author Dr. Philippe Gautret, and authors Professors Philippe Parola,  Philippe Brouqui, Philippe Colson, and Bernard La Scola, “disagreed with the retraction and dispute the grounds for it”.

Then US president Donald Trump touted Hydroxychloroquine several times as an effective treatment for COVID-19.