Intended for healthcare professionals


The perils of preprints

BMJ 2020; 370 doi: (Published 17 August 2020) Cite this as: BMJ 2020;370:m3111
  1. May C I van Schalkwyk, NIHR doctoral research fellow1,
  2. Thomas R Hird, research fellow2,
  3. Nason Maani, Harkness fellow in healthcare policy and practice1 3,
  4. Mark Petticrew, professor of public health1,
  5. Anna B Gilmore, professor of public health2
  1. 1Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
  2. 2Tobacco Control Research Group, Department for Health, University of Bath, Bath, England, United Kingdom
  3. 3School of Public Health, Boston University, Boston, MA 02118, USA
  1. Correspondence to: May CI van Schallkwyk may.vanschalkwyk{at}

Their use and platforms require greater scrutiny

Preprints—manuscripts that have not undergone peer review—were first embraced in physics, catalysed by the creation in the early 1990s of, an open online repository for scholarly papers.1 It was not until 2013 that similar initiatives were embraced by the biological and then medical sciences,2 and novel publishing platforms continue to emerge. Some commentators believe the potential for harm is outweighed by the benefits,134 but others have raised specific concerns regarding medical preprints and mitigating the risk of harm to the public.2 These discussions need to be revisited in the context of the covid-19 pandemic, which has been accompanied by an explosion of preprint publications.

Shaping global discourse

An analysis focusing on studies estimating the R0 of SARS-CoV-2 drew attention to the powerful role of preprints in shaping global discourse about covid-19 transmissibility. While showing the benefits that preprints may confer when adopting a consensus based approach—where data is extracted from multiple studies to observe trends and obtain an average with or without the exclusion of outliers—the authors also identify risks—matters of credibility and misinformation, both intentional and unintentional5—which may be increased where there are vested interests involved.

Notably, two linked preprint publications examining the association between smoking and covid-19,67 which were widely disseminated before …

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