model of the USS Enterprise spaceship
model of the USS Enterprise spaceship

The Top Retractions of 2021

From Star Trek to ivermectin, we look back on some of the most notable about-faces in publishing this year.

Retraction Watch
Dec 21, 2021


Since the start of the pandemic, journals have retracted more than 200 COVID-19–related papers and counting, most of them in 2021. But such papers represent only about 5 percent of the more than 3,000 retractions we’ve indexed this year in the Retraction Watch Database. In what has become an annual tradition, here we present the top retraction stories of the year.

1Like a lot of people, Victor Grech, a pediatric heart specialist in Malta, really likes Star Trek. The problem is that Grech was able to turn an Elsevier journal called Early Human Development into something of a scientific fanzine, publishing dozens of articles for the periodical that were in a galaxy far, far outside the scope of its editorial interests. The publisher learned about the problematic papers in late 2020 from Hampton Gaddy, an undergrad at the University of Oxford in the UK. Grech’s articles covered topics such as the role of nurses in Star Trek, the banality of evil in Star Trek, and the portrayal of doctors in, you guessed it, Star Trek. Grech eventually lost more than two dozen papers to retraction.

See “When Researchers Sound the Alarm on Problematic Papers

2In 2015, officials at the University of Colorado Denver concluded that one of its former faculty members, Hari Koul, needed to correct or retract nine papers over concerns about problematic images in the articles. But six years later, most of those articles remained intact—and many of the journals involved said they’d never heard of the investigation. After Retraction Watch reported on the delay, journals pulled three articles by Koul, who had left Denver for Louisiana State University Health Science Center (LSU HSC) in Shreveport and eventually ended up at LSU HSC New Orleans. Then, after local media reported on other allegations Retraction Watch had mentioned, LSU HSC New Orleans said it was investigating, and Koul stepped down from his post as department chair.

3When the journal Vaccine published a study in June claiming that COVID-19 vaccinations killed two people for every death they prevented, the scientific community was outraged. Two members of the journal’s editorial board stepped down to protest the article, which was written by Harald Walach, described on his Wikipedia page as a “parapsychologist and advocate of alternative medicine.” Vaccine quickly issued an expression of concern for the paper and subsequently retracted it. Meanwhile, Walach, whose institution in Poland terminated his position in response to the controversy, has defended his group’s analysis, saying that the data, while imperfect, were analyzed correctly. He also lost another paper, in JAMA Pediatrics, on COVID-19 and masks for children.

4Last year, scientists began to express doubts about the validity of data they’d been receiving from Jonathan Pruitt, a behavioral ecologist with a prestigious position at McMaster University in Canada, whose field research on spiders had helped underpin many publications. Pruitt’s articles quickly began to fall, and over the next year he lost a dozen papers. Late this year, Pruitt’s doctoral dissertation, which he’d received from the University of Tennessee, Knoxville, was withdrawn. Pruitt was placed on paid leave from McMaster and removed from the prestigious Canada 150 Chairs website.

5When Cyriac Abby Philips, a gastroenterologist in India, published a 2018 paper about a young woman who’d suffered liver disease after taking herbal supplements, he didn’t think that three years later he’d be considering suing the journal for defamation. Philips’s legal troubles started when he and his colleagues published their case study in the Journal of Clinical and Experimental Hepatology, an Elsevier title. Herbalife, which makes dietary supplements including the ones the patient took, pressured the journal, which ultimately decided to retract the work for “legal reasons,” as stated in the original retraction notice. That notice was later changed to say that the “scientific methodology, analysis and interpretation of data underlying the article were insufficient”—a claim Philips called “highly defamatory.” He threatened to sue the publisher and the journal for the equivalent of US $1.35 million. The retraction notice promptly was changed again, and now cites legal pressures as it initially did. 

6Retractions often take years, but not in this case. Barely a month after the publication of a paper claiming female scientists fare better under male mentors, Nature Communications retracted the article amid a storm of criticism. Written by a group from the Abu Dhabi campus of New York University, the paper was lambasted from the moment it appeared online in mid-November. As one statistician tweeted, the paper “doesn’t tell us much about the impact of gender on mentorship but it sure does tell us that the statistics community needs to do a better job teaching scientists about correlation, causation, and confounding.” The authors said they agreed with the journal’s decision and said they felt “deep regret that the publication of our research has both caused pain on an individual level and triggered such a profound response among many in the scientific community.”

7Pierre Kory, then of the University of Wisconsin School of Medicine and Public Health, testified to Congress in May 2020 that MATH+—an intensive care regimen that includes methylprednisolone, ascorbic acid, thiamine, heparin, and co-interventions—slashed the risk of death from COVID-19 by 75 percent compared with other regimens. Then, last December, he and his colleagues published a paper in the Journal of Intensive Care Medicine about MATH+ (to which they later added the controversial drug ivermectin) saying as much, prompting questions from other experts about whether the effectiveness of the approach was overstated. Those concerns appear to be warranted. In November, the journal retracted Kory’s paper, citing inaccurately reported data from one of the study sites in the analysis.

8In late 2020, the journal Eurosurveillance announced that, in response to an international petition, it was looking more closely at a paper it had published at the start of the year on the validity of PCR testing for SARS-CoV-2 (at the time called 2019-nCoV). The news heartened critics of the article, who argued that PCR testing wasn’t capable of identifying the virus—and thus, positive tests were meaningless and shouldn’t be used to guide public policy, especially economically damaging steps such as lockdowns. But two months later, the editors issued a statement saying that the paper would stand (or more precisely, “the criteria for a retraction of the article have not been fulfilled”).

9Advocates for the use of ivermectin to treat COVID-19 have little in the way of robust evidence to support their belief that the deworming drug is effective against the infection. One study many ivermectin fans pointed to this year appeared in Viruses in the spring. The randomized controlled trial purportedly found that a single dose of the drug led to “fewer symptoms, lower viral load and reduced hospital admissions.” Except that wasn’t true. As BBC News reported, the study “was found to have blocks of details of 11 patients that had been copied and pasted repeatedly—suggesting many of the trial’s apparent patients didn’t really exist.” The authors acknowledged that they’d mixed up their data files, and in November the journal retracted the paper, but not before the study had become part of a meta-analysis on the virtues of ivermectin for COVID-19, which as of this writing remains uncorrected.

10Finally, one of our favorites for the year. The Arabian Journal of Geosciences was forced to retract 44 articles from a special issue after readers pointed out that they appeared to be utter gibberish. The first clue? The titles read like a bunch of graduate students playing drunk Mad Libs: “Neural network–based urban rainfall trend estimation and adolescent anxiety management”; “Distribution of earthquake activity in mountain area based on embedded system and physical fitness detection of basketball.” A guest editor of the journal, which is owned by Springer Nature, at one point blamed an email hack for the nonsense articles. In fact, the 44 were just the tip of the sand dune for Springer Nature. More than 400 papers in journals owned by the company—and hundreds more at journals owned by Elsevier—have been flagged for similar problems. 

Ivan Oransky and Adam Marcus are the founders of Retraction Watch. Email them at, follow them on Twitter @RetractionWatch, and sign up for their daily newsletter.

Correction (January 3): This article originally referred to LSU HSC Shreveport and LSU HSC New Orleans as campuses of the same university. While in the same university system, they are separate institutions. The Scientist regrets the error.