The text below was copied word for word from Next Phase of the NIH Preprint Pilot Launching Soon - NCBI Insights (January 9, 2023):
"The National Library of Medicine (NLM) announced plans to extend its NIH Preprint Pilot in PubMed Central (PMC) and PubMed beyond COVID-19 to encompass all preprints reporting on NIH-funded research. The second phase of the pilot, launching later this month, will include preprints supported by an NIH award, contract, or intramural program and posted to an eligible preprint server on or after January 1, 2023.
Preprints are complete and public drafts of scientific articles that have not yet been peer reviewed. Scientists may post preprints to speed dissemination of their research, establish priority, or obtain feedback. (From statement on preprints from NIH Grants website.)
Since June 2020, the NIH Preprint Pilot has been exploring new approaches to increase the discoverability of NIH-supported research results made available as preprints. The first phase focused on preprints reporting COVID-19 related research supported by NIH. (A full report on Phase 1 is available as a preprint, linked below.) In preparation for the launch of this second phase, we have updated PMC and PubMed site features to help users of these databases incorporate the increased volume of preprints into their discovery workflows."
Indexed preprints will be clearly identified in an article's record: