Effective July 1, 2025, a new NIH Public Access Policy went into effect.
This policy now removes the 12-month embargo, requiring all Author Accepted Manuscripts accepted for publication on or after July 1, 2025 to be made immediately available in PubMed Central upon publication.
Author Accepted Manuscripts are defined by the NIH as, "the author’s final version that has been accepted for journal publication and includes all revisions resulting from the peer review process, including all associated tables, graphics, and supplemental material."
Three Critical Steps to Maintaining Compliance
1. Ensure submission of work to PubMed Central upon notice of publication
2. Ensure language about NIH funding and PubMed Central requirements are clearly defined in the work
3. All reports, proposals, etc. must include a PubMed Central Identifier (PMCID) when demonstrating compliance with NIH
More Information on Steps 1 and 3
1. You must submit your Author Accepted Manuscript to PubMed Central for public availability without embargo upon publication date. It is not sufficient for the work to be available on a journal or publisher's website; it must be submitted for immediate release to PubMed Central. With that, there are some journals that automatically deposit the work in PubMed Central. To see which journals currently have this agreement, visit this link from the NIH. Ensure that the agreement is active and check with the journal/publisher.
3. When you submit your work to PubMed Central, it will be assigned a PubMed Central Identifier (PMCID). If you have a NIH Manuscript Submission identifier (NIHMSID), that may be used instead of a PMCID for up to three months following the publication date.
This chart, created by Dana Haugh, Harvey Cushing/John Hay Whitney Medical Library, Yale, (and copied from University of Pittsburgh's HSLS LibGuide) can also help explain:

This section summarizes key points from NIH policy as of NOT-OD-21-013. Further explanations and clarifying details are available at https://grants.nih.gov/policy-and-compliance/policy-topics/sharing-policies.
NIH defines the type of data that is covered by their sharing policy as:
The recorded factual material commonly accepted in the scientific community as of sufficient quality to validate and replicate research findings, regardless of whether the data are used to support scholarly publications. Scientific data do not include laboratory notebooks, preliminary analyses, completed case report forms, drafts of scientific papers, plans for future research, peer reviews, communications with colleagues, or physical objects, such as laboratory specimens.
Data resulting from research involving human subjects must be managed and shared appropriately to protect privacy. NIH accepts a variety of strategies for doing this when sharing data, including deidentification, redaction, or sharing via controlled-access repositories. For more details, visit https://grants.nih.gov/policy-and-compliance/policy-topics/sharing-policies/dms/privacy.