Another Ivermectin-COVID-19 Paper Is Retracted

Retraction Watch Staff

May 11, 2022

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

A paper on the potential use of ivermectin to treat Covid-19 has been retracted for a litany of flaws, joining at least 10 other articles on the therapy some liked to promote without evidence to fall. 

The article was part of a special issue of Toxicology Reports on Covid-19 that has received an expression of concern; six of the eight articles still have EoCs. Two, including one "Why are we vaccinating children against COVID-19?," have now been retracted.

The newly retracted article, "Use of ivermectin in the treatment of Covid-19: A pilot trial," was written by a group from  Brazil and the United States and appeared in March 2021.

According to the retraction notice

This article has been retracted: please see Elsevier Policy on Article Withdrawal (

The article has been retracted at the request of the Founding Editor, Prof. Lawrence H. Lash, on the basis that there is clear evidence that the findings are unreliable:

Additional external review of this published paper raised several concerns. While a properly conducted clinical trial is certainly welcome, the experimental design of this study lacks sufficient details for some of the methods and approaches, uses inappropriate or inadequate statistical analysis, and presents unclear data interpretation.

The conclusions and statements of the authors cannot be readily supported by the information presented in the paper.

Additionally, no reference is made to the well-known controversies that surrounded the recommended use of ivermectin to treat infections with COVID-19. The omission of any discussion of these controversies in the present paper makes the paper misleading and unacceptable.

The article has yet to be indexed in Clarivate Analytics' Web of Science, but it did find its way into an official document from the South African government on Covid-19. 

Lash, who led the inquiry into the special issue, told us that:

All papers in the Special Issue underwent an additional, post-publication peer review that I oversaw at the request of the Publisher for Toxicology Content at Elsevier. While I know that there were a significant number of complaints and adverse comments received about one of the other papers in the Special Issue (the one involving vaccination of children), I am not aware of specific complaints about this paper. My task was to organize an independent, post-publication review of all papers in the issue.

The retraction notice posted for this paper, which was a small clinical trial involving the use of the antifungal drug ivermectin as a potential therapeutic agent for Covid-19 infection, basically highlights all the conclusions of the post-publication peer review. As noted, there were concerns with the design of the pilot clinical trial that raised questions about the reliability of the conclusions. Moreover, the authors made no acknowledgement of any of the well-publicized controversies regarding potential use of this drug. Hence, the portrayal of the work was viewed as unbalanced.

We also asked Lash if he believed a more thorough peer review might have flagged the flaws prior to publication: 

I cannot really speak to that as I had not been involved with the journal in any capacity since 2018 (I stepped down as the Founding Editor in February 2017 and served as a peer reviewer of a few manuscripts during the subsequent year). However, both my review of the paper and that of the individual I recruited as an additional reviewer readily noted concerns; had I been the initial handling Editor, I would have not considered the manuscript for publication in its current form.

By our count, 224 papers on Covid-19 have now been retracted.