The vast majority of medical journals now allow articles to appear as preprints before they are peer reviewed and officially published, a study finds.

Out of 100 top clinical journals, only one completely disallows preprints, 13 are willing to accept preprinted studies for peer review and publication on a case-by-case basis, and 86 have no restrictions on preprints, according to the report in JAMA Network Open.

The findings represent a major change in medical publishing, says study coauthor Dr Harlan Krumholz, a cardiologist and professor of medicine at Yale University in California, and one of the cofounders of the preprint server medRxiv.org.

To take a look at how acceptable preprints had become, Dr Krumholz and colleagues identified the 100 top-ranked journals that publish original clinical research.