Flawed ivermectin preprint highlights challenges of COVID drug studies
“Before its withdrawal, the paper was viewed more than 150,000 times, cited more than 30 times and included in a number of meta-analyses that collect trial findings into a single, statistically weighted result. In one recent meta-analysis in the American Journal of Therapeutics that found ivermectin greatly reduced COVID-19 deaths4, the Elgazzar paper accounted for 15.5% of the effect”.
Throughout the pandemic, the anti-parasite drug ivermectin has attracted much attention, particularly in Latin America, as a potential way to treat COVID-19. But scientists say that recent, shocking revelations of widespread flaws in the data of a preprint study reporting that the medication greatly reduces COVID-19 deaths dampens ivermectin’s promise — and highlights the challenges of investigating drug efficacy during a pandemic.
“I was shocked, as everyone in the scientific community probably were,” says Eduardo López-Medina, a paediatrician at the Centre for the Study of Paediatric Infections in Cali, Colombia, who was not involved with the study and who has investigated whether ivermectin can improve COVID-19 symptoms. “It was one of the first papers that led everyone to get into the idea ivermectin worked” in a clinical-trial setting, he adds.
The paper summarized the results of a clinical trial seeming to show that ivermectin can reduce COVID-19 death rates by more than 90%1 — among the largest studies of the drug’s ability to treat COVID-19 to date. But on 14 July, after internet sleuths raised concerns about plagiarism and data manipulation, the preprint server Research Square withdrew the paper because of “ethical concerns”.
Ahmed Elgazzar at Benha University in Egypt, who is one of the authors on the paper, told Nature he was not given a chance to defend his work before it was removed.
Early in the pandemic, scientists showed that ivermectin could inhibit the coronavirus SARS-CoV-2 in cells in laboratory studies2. But data on ivermectin’s efficacy against COVID-19 in people are still scarce, and study conclusions conflict greatly, making the withdrawal of a major trial particularly noteworthy.
Although the World Health Organization advises against taking ivermectin as a COVID-19 treatment outside clinical trials, the over-the-counter drug has become popular in some regions of the world. Some view it as a stopgap until vaccines become available in their areas, even though it has not yet been proven effective; scientists worry that it will also be seen as an alternative to vaccines, which are highly effective.