An investigation conducted by Australian and Swedish researchers found that the most cited paper among the hundreds of COVID-19 research papers that have been withdrawn is a retracted study linking the drug hydroxychloroquine to increased mortality. The study, titled “Hydroxychloroquine or chloroquine with or without a macrolide for treatment of COVID-19: a multinational registry analysis”, had 1,360 citations even after its retraction. The researchers involved in the analysis, from the University of Wollongong, Linköping University, and Western Sydney Local Health District, noted that most researchers fail to identify retracted research papers they cite, leading to serious implications for the reliability of scientific literature. Over 100 medical professionals raised major concerns with the study, including the absence of ethics review, unusually small reported variances, and data discrepancies. The World Health Organization temporarily stopped the trial of hydroxychloroquine on COVID-19 patients following the study’s publication, and France changed its national recommendation and halted all trials. A total of 337 research papers on COVID-19 have been retracted, with more expected as the investigation continues.