Table of Contents: 2024 NOVEMBER–DECEMBER No. 461
Annual MeSH Processing for 2025. NLM Tech Bull. 2024 Nov-Dec;(461):e3.
The National Library of Medicine (NLM) is currently involved in Annual MeSH Processing (AMP) for 2025 Medical Subject Headings (MeSH). These include changing the MeSH main headings and subheadings as well as Supplementary Concept Records (SCRs) that standardize names and associated numbers for chemicals, protocols, diseases, and organisms that are not main headings. The MeSH edits include maintaining existing MEDLINE citations to conform with the 2025 version of MeSH, and other global changes.
This article informs and directs the users to the notable changes made to MeSH during the NLM annual maintenance for 2025:
The MeSH Browser points to the 2024 MeSH vocabulary with a link to the 2025 MeSH vocabulary. On December 5, the default will switch to 2025 and the alternate link has been routed to 2024 MeSH. Searchers should consult the Browser to find MeSH headings of interest and their relationships to other headings. The Browser contains MeSH heading records that may include Scope Notes, Annotations, Entry Terms, History Notes, Allowable Qualifiers (Subheadings), Previous Indexing, and other information. It also includes Subheading records and SCRs for substances, diseases, and organisms that are not MeSH headings.
You will be able to download 2025 MeSH from links on the NLM Data Distribution page for MeSH Data on December 4, 2024. An announcement with further details for the release of 2025 MeSH XML Data will be announced in December 2024.
MeSH 2025 Update
Beginning with the release of 2023 MeSH, NLM now offers reports detailing the changes to the MeSH vocabulary. The MeSH 2025 Update reports detail the changes to MeSH terms that are performed during AMP. The MeSH Update allows users to view changes made to the MeSH vocabulary in various formats (CSV, PDF, HTML) as well as providing exportable reports (CSV, JSON, RDF, and XML). These include detailed reports regarding:
Note: Typically, NLM does not retroactively re-index MEDLINE citations with new MeSH heading concepts. Therefore, searching PubMed for a new MeSH term tagged with [mh] or [majr] effectively limits retrieval to citations indexed after the term was introduced. Searchers may consult the MeSH database to see the previous indexing terms most likely used for a particular concept before the new MeSH heading was introduced. For terms without previous indexing information, consider the next broader term(s) in the MeSH hierarchy. For more searching guidance, see the on-demand class MeSH Changes and PubMed Searching.
Several notable changes are being made to Publication Types for MeSH 2025. First, an exception will be made to NLM's typical rule to provide retroactive indexing for two new Publication Types: "Network Meta-Analysis" and "Scoping Review." A similar exception was previously made in 2019 for the introduction of "Systematic Review."
"Network Meta-Analysis" is being converted from a Descriptor to a Publication Type. On existing citations, the Descriptor will be replaced with either the Publication Type or the corresponding term "Network Meta-Analysis As Topic" as appropriate. This will extend the scope of the "Network Meta-Analysis" Publication Type indexing to the introduction of the original term in 2017. "Scoping Review" will replace "Review" or "Systematic Review" on appropriate citations extending back to 2020, the first year this term appears in MEDLINE.
Additionally, NLM will discontinue indexing use of the following Publication Type terms:
As with previously discontinued Publication Types, which include "Government Publication," "Newspaper Article," "Overall," and "Scientific Integrity Review," these Publication Types will continue to exist in MeSH, appear on existing citations, and be searchable in PubMed. However, they will no longer be applied to new citations.
NLM expects to temporarily suspend the addition of fully indexed MEDLINE citations to PubMed the week of January 6, 2025. NLM will continue to add publisher-supplied and in-process citations.
MEDLINE citations with updated MeSH are anticipated to be in PubMed by mid-January 2025. For instruction on how to adjust historical searches to changes in MeSH, see the on-demand class MeSH Changes and PubMed Searching.
