The malaria drug chloroquine continues to be scrutinized

Lisa Vogel studied departmental journalism with a focus on medicine and biosciences at Ansbach University and deepened her journalistic knowledge in the master's degree in multimedia information and communication. This was followed by a traineeship in the editorial team. Since September 2020 she has been writing as a freelance journalist for

More posts by Lisa Vogel All content is checked by medical journalists.

It was one of the rare large studies that seemingly produced clear results in the corona pandemic. Now the journal withdrew them.

The specialist journal "The Lancet" has withdrawn a study on the use of chloroquine and hydroxychloroquine against the new coronavirus. Three of the four authors pointed out that they could not dispel doubts about the accuracy of the data they used, as the journal announced on Thursday evening.

The effectiveness of the agents used to date against malaria against the lung disease Covid-19 is currently being tested in numerous studies. Previous studies have not provided any reliable evidence that it improves symptoms in sick people or shortens the duration of the illness.

Studies resumed

According to information in the now withdrawn study, the two active ingredients should probably not be suitable for the treatment of Covid-19 and possibly even increase the death rate and lead to cardiac arrhythmias.

The researchers from the USA and Switzerland led by Mandeep Mehra from Harvard Medical School had published the study in "The Lancet" on May 22nd. According to the study, they had evaluated data from a good 96,000 patients. Because of the negative results, several studies on chloroquine and hydroxychloroquine were suspended. The latter is also under special observation because US President Donald Trump has repeatedly praised it as a miracle cure.

Before the study was withdrawn, there had been considerable doubts about the publication. "Lancet" itself had already published an official warning ("Expression of Concern"). There are "serious scientific questions" about the data provided by the researchers.

Unrealistic numbers

According to the Science Media Center, one of the inconsistencies is that the study relates to a higher number of Covid-19 patients who died in hospital in Australia than were actually reported in Australia as a whole. In addition, the authors claimed to have processed the data of 4402 patients in Africa in the study - according to critics, however, it is unlikely that African hospitals could provide detailed electronic health records for so many patients.

According to the "Lancet", the data collection goes back to a Chicago-based company. The process of the so-called peer review by experts is neither intended nor able to check the quality of the underlying data, said Ulrich Dirnagl, director of the Department of Experimental Neurology at the Charité in Berlin, who was not involved in the study. "Often it remains a kind of" reality check "of the scientific question, the methodology used and the results."

Quality control under time pressure

In times of a pandemic, in which researchers and journals tried to publish under extreme time pressure, the review process is even less able to detect errors and manipulations. There are currently a lot of studies with poorly collected or insufficient data, he criticized.

The World Health Organization (WHO) had already announced on Wednesday that suspended tests with hydroxychloroquine in Covid 19 sufferers will be resumed. The product is part of a research series coordinated by the WHO with more than 3,500 patients in 35 countries. These attempts were also temporarily suspended at the end of May after the "Lancet" study. (lv / dpa)

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