Keyboard controls: Space bar - toggle play/pause; Right and Left Arrow - seek the video forwards and back; Up and Down Arrow - increase and decrease the volume.
Webinar Materials
For MLA CE credit, please register at NNLM.gov.
For more information about MeSH:
- MeSH homepage
- 2025 MeSH On-Demand
- Learn about MeSH
- MeSH Changes and PubMed Searching On-Demand class
Transcript
Welcome to the 2025 MeSH Highlights. My name is Louise To. I'm a Technical Information Specialist at the National Library of Medicine. This year we are offering MeSH Highlights as a recording, but we encourage you to submit questions via the Moodle course or write to NLM's Help Desk. In this presentation, we will point to several resources, which you can find listed in the Recommended Resources section.
Every year, updates are made to the Medical Subject Headings, also known as MeSH, the NLM controlled vocabulary thesaurus used for indexing articles for PubMed. This annual training aims to introduce those changes and provide examples of how the changes may affect you as a PubMed searcher. The intended audience includes librarians, cataloguers, and really any PubMed searchers that are somewhat familiar with MeSH's structure. If you're not familiar with MeSH's structure or PubMed, we've listed available training in the Recommended Resources section.
In addition to being familiar with PubMed, this webinar will also be referring to the MeSH database, which displays MeSH records and can be used to help you construct search strings in PubMed.
Our agenda begins with an overview of the number of changes that have been implemented for MeSH 2025. The webinar will illustrate examples of changes from different branches of MeSH, and we'll discuss how these changes may apply to searchers.
Before I get into the numbers, I want to point you to the NLM Technical Bulletin, which provides updates on NLM's various offerings. MeSH has been and will continue to share drafts of changes for the next MeSH cycle. You can find these on the What's New in MeSH page.
For MeSH 2025, we have a total of 30, 956 Main Headings, 192 of them are newly added. As far as Supplementary Concept Records, also known as SCRS, the count is at 323, 939, with 1001 being new.
This slide breaks down the new MeSH terms by branch, with many new MeSH headings falling under Category G. Phenomena and Processes and Category L. Information Science. If you are interested to dig into the data, the annual MeSH Processing Technical Bulletin article provides instructions on how to access the update reports for the MeSH 2025 release. These reports can be found in the NLM Data Discovery catalog.
While this presentation will focus on how the new updates to MeSH will affect PubMed searching, I'll note that MeSH 2025 has also been adopted in the NLM catalog. If you'd like more details on the use of MeSH 2025 in cataloguing, please refer to the Technical Bulletin article published in December.
If you are looking for more detailed instruction, you can also refer to the most recent recording of the Cataloguing with MeSH webinar that was hosted last year.
Now, let's dive into the examples of changes.
We'll begin with notable changes to publication types, beginning with the addition of a new term. SCOPING REVIEW is a new publication type for 2025, and it is defined as literature that provides an overview of the available evidence without producing a summary answer. In contrast, SYSTEMATIC REVIEW is defined as literature that examines evidence to provide an answer to a specific clinical research question and assess the validity of the findings of the included studies. Systematic reviews synthesize the best available research on a specific clinical intervention, while scoping reviews map the body of literature on a topic. Scoping reviews do not provide statements that guide clinical decision making, and they are often performed as a precursor to a systematic review. Because a more specific term did not exist, scoping reviews were previously assigned the publication type Systematic Review. With the MeSH 2025 update, scoping review articles will now be assigned the publication type Scoping Review. An exception will be made to NLM's typical rule to provide retroactive indexing for this new publication type.
Here's an example of a scoping review in PubMed. Before 2025, it was assigned the publication type Systematic Review.
With the MeSH 2025 update, this article will be reassigned the term Scoping Review.
If you are using the Systematic Review filter in PubMed, please note that this term will now exclude articles indexed as Scoping Reviews, such as Systematic Scoping Review, Scoping Systematic Review, and Scoping Umbrella Review. The scoping aspect of these reviews takes precedence in indexing.
The next example illustrates two changes to a main heading. NETWORK META-ANALYSIS is defined as meta-analysis of randomized trials in which estimates of comparative treatment effects are visualized and interpreted from a network of interventions that may or may not have been evaluated directly against each other. In 2025, this term becomes a publication type that is used for the original report of the conduct or results of a specific network meta-analysis study.
To account for literature that describes the general design, methodology, economics, etc. of network meta-analyses, MeSH 2025 has added the main heading of NETWORK META-ANALYSIS AS TOPIC. Like the previous example of Scoping Review, an exception will be made to NLM's typical rule to provide retroactive indexing on existing citations. Network Meta-Analysis will become either the articles publication type or will be changed to the main heading Network Meta-Analysis As Topic, whichever is most appropriate given the articles content.
Before 2025, a PubMed search for the MeSH term Network Meta-Analysis would return about 6,970 results.
With the MeSH 2025 update, you may notice a change in the number of results as we work on retroactive indexing for this term. In the meantime, we recommend updating your search strings to the new publication type or the AS TOPIC term based on your query needs.
Whenever you notice a change in the number of results, we recommend you check your terms using the MeSH Database. In the MeSH Database, you'll see that searching Network Meta-Analysis gives us 2 results, including both the publication type and the AS TOPIC main heading. Searching in the MeSH database will retrieve the MeSH records that contain your keywords of interests, and from there you can check for any changes and determine which are most appropriate for your search.
Another notable change is that several publication types have been discontinued. Based on analytics, we see that PubMed users are not searching for these publication types, and a few of these publication types are outdated. For example, the journals that were assigned newspaper article are no longer being published. Discontinuation means NLM will no longer apply these publication types to new Medline citations going forward. However, they will remain in MeSH and they will not be removed from old citations. Publishers can continue to submit certain publication types. NLM cataloguers will continue to use the majority of these publication types, and these terms will still be available to those who catalog with MeSH. As users, you can still conduct search queries in PubMed using these terms.
The next example illustrates how a new term might be used in conjunction to an existing term. For MeSH 2025, the term PLAIN LANGUAGE SUMMARIES has been added and it is defined as short summaries of research articles written in clear, easy-to-understand language. Intended to be a useful way of communicating health research to a non-expert reader. This new trend of adding plain language summaries for research articles intends to make science more accessible to non-scientists.
You can encounter plain language summaries in a couple of ways. On this slide is an example of a PubMed article with a plain language summary of a couple of sentences appended to the abstract's conclusion.
And there are also complete rewrites of entire articles in plain language. This slide displays an original article on the left side along with its plain language rewrite on the right side. This plain language article is formatted like an infographic and has learning tools included in the article, like a pronunciation guide and a glossary. The MeSH term Plain Language Summaries is not being used as a publication type because it can show up in these different ways. While NLM is developing our policy regarding this new type of citation, articles about plain language summaries like how to write them and how they are used will also be indexed with this MeSH term.
Of the existing publication types, PATIENT EDUCATION HANDOUT is a related term. It was established as a MeSH term in 2002, and it is defined as works consisting of a handout or self-contained informative material used to explain a procedure or a condition or the contents of a specific article in a biomedical journal and written in non-technical language for the patient or consumer. Since the scope note of Patient Education Handout is inclusive of biomedical articles, we recommend including this publication type in your queries.
With the MeSH 2025 update, searching plain language summary without quotes will trigger the new MeSH term, and it will also search the phrase across all fields, providing a broad search. Remember, new terms need some time to accumulate results. Broadening your search may help you retrieve plain language summaries in the database that were indexed before this MeSH term was created. Since there's overlap in scope, adding patient education handout to your search string will also help you retrieve even more articles.
Let's switch gears and talk about activities of daily living. The example illustrates an entry term getting promoted to main heading. INDEPENDENT LIVING is defined as a housing and community arrangement that maximizes independence and self determination. Before 2025, AGING IN PLACE and COMMUNITY DWELLING were entry terms to Independent Living. With the MeSH 2025 update, Aging In Place is promoted to the status of a main heading and made a child term of Independent Living, and Community Dwelling becomes its entry term.
Previously, if you search the phrase Aging In Place without quotes or tags, PubMed will pull up the MeSH term Independent Living, yielding about 52, 498 results. This triggering is referred to as PubMed's automatic term mapping, also known as ATM. ATM is a mechanism by which untagged search terms are matched against a translation table and triggers the inclusion of MeSH terms in your query. Since Aging In Place was listed as an entry term to Independent Living in the translation table, the MeSH term Independent Living was added to the query.
With the new update, the same search will no longer trigger Independent Living. Instead, it will trigger the new MeSH term Aging in Place. If you use this phrase in your search strings, you may notice that the number of results has dropped. The addition of narrower MeSH terms like this one benefits searchers because this new term will retrieve more specific articles compared to its parent term.
In the category of organic chemicals, I'll point to an example that illustrates the restructuring of the MeSH tree due to the addition of new terms. BISPHENOL A-GLYCIDYL METHACRYLATE is defined as the reaction product of Bisphenol A and glycidyl methacrylate that undergoes polymerization when exposed to ultraviolet light or mixed with the catalyst. It is used as a bond implant material in dentistry. Back in MeSH 2024, this term was treated directly under PHENOLS. For MeSH 2025, this branch gained two more levels of classification with the addition of BISPHENOLS and BISPHENOL A, B, F and S Compounds. These compounds are commonly used in the production of polymers. Bisphenol A-glycidyl methacrylate then became a child term of Bisphenol A Compounds. The addition of these broader terms helps users take advantage of MeSH's tree structure and PubMed's mechanism of automatic explosion. Automatic explosion refers to the inclusion of child terms when a MeSH term is searched.
When you search for Bisphenol A Compounds in PubMed without quotes or tags, it will trigger the main heading and its child term according to the Mesh tree. The main heading Bisphenol A Compounds will automatically explode to include the articles indexed with the term Bisphenol A-Glycidyl Methacrylate.
When searching Bisphenol A in the MeSH database, you may notice that there are several results that are supplementary concept records. Please note, automatic explosion only applies to terms that are designated as main headings. Supplementary concept records are not organized in the MeSH tree structure and therefore they will not trigger automatic explosion. Be sure to read through each result record in deciding which term may benefit your search.
This next example on amphibians illustrates the renaming of a main heading with an existing entry term. URODELA is an order of the Amphibia class, which includes salamanders and newts. This term in 2024 had four entry terms, including AMPHIUMA; CAUDATA; EEL, CONGO; and SALAMANDERS.
For 2025, Caudata becomes the main heading and Urodela becomes an entry term, alongside a few new plural variations on existing entry terms. This change was made to align with the NCBI Taxonomy database, which is a curated classification and nomenclature for all of the organisms in public sequence databases.
Since the previous term was added as an entry term, a PubMed search for Urodela without quotations will automatically translate your search to include the new MeSH term Caudata. In other words, PubMed will likely recognize what you are looking for.
If you have saved search strings with Urodela in quotes along with the MeSH tag, then you'll notice that the search string is not retrieving any results because it is not triggering the newly renamed MeSH term of Caudata.
To trigger the newly renamed MeSH term of Caudata in your search translation, you'll want to remove the quotations so that PubMed can recognize Urodela as the entry term and retrieve the relevant indexed results.
Finally, the last example is in the branch of Information Science. Let's look at an example that illustrates how abbreviations are handled. NON-FUNGIBLE TOKENS are defined as digital certificates in the form of data recorded on a blockchain that signify ownership of associated digital items such as images, music, or videos not contained in the certificate data itself. Non-Fungible Tokens are also known as NFTs. Abbreviations are usually listed as entry terms within MeSH records.
Searching for part of an entry term won't always trigger PubMed to include the heading that the entry term belongs to. On this slide you see a PubMed search for NFT without quotes or tags. This search does not trigger a specific MeSH term because NFT can refer to many different things. Do you mean Neurofibrillary Tangle which is a hallmark of Alzheimer's? Or do you mean one of these two hard to pronounce chemicals known as NFT-202 or FANFT?
When searching the phrase NFT in the MeSH Database, it recognizes NFT to be part of three records. From this list, you can determine which terms are most appropriate for your search.
We've covered several examples of how MeSH 2025 changes may affect PubMed searching. If you want to learn more, we recommend taking the Mesh Changes and PubMed Searching On Demand class. This course will take a deeper dive into how the MeSH changes can affect you, including more in-depth examples of using the MeSH Database to support your searching.
This concludes the 2025 MeSH Highlights presentation. If you have any questions, you can submit via the questions section or you can also contact the NLM Help Desk.
Last Reviewed: May 23, 2025