What’s new in 2021
This article highlights the changes in the DeCS/MeSH vocabulary.
Totals by type of terminology
| Term types | language | 2020 | 2021 | Variation | |
| amount | % | ||||
| Main Heading (Descriptor) terms | English | 34041 | 34294 | 253 | 0,74% |
| Spanish (America) | 34041 | 34294 | 253 | 0,74% | |
| Spanish (Spain) | 34041 | 34294 | 253 | 0,74% | |
| Portuguese | 34041 | 34294 | 253 | 0,74% | |
| Entry terms | English | 218803 | 228525 | 9722 | 2,03% |
| Spanish (America) | 60670 | 66118 | 5448 | 8,98% | |
| Spanish (Spain) | 51380 | 56740 | 5360 | 10,43% | |
| Portuguese | 67078 | 74963 | 7885 | 11,75% | |
| Qualifier terms | English | 77 | 77 | 0 | 0,00% |
| Spanish (America) | 77 | 77 | 0 | 0,00% | |
| Spanish (Spain) | 77 | 77 | 0 | 0,00% | |
| Portuguese | 77 | 77 | 0 | 0,00% | |
| Total | 534403 | 563830 | 29427 | 5,51% | |
Changes for 2021
- 277 MeSH descriptors and 12 exclusive DeCS descriptors were added
- 17 descriptors were modified in English, of which 3 are exclusive of DeCS
- 39 descriptors were modified in Spanish, of which 22 are exclusive of DeCS
- 53 descriptors were modified in Portuguese, of which 36 are exclusive of DeCS
- 17 descriptors were eliminated
- 129 scope notes have been updated in English, Spanish and Portuguese
- 1209 indexing annotations have been updated in English, Spanish and Portuguese
Subcategories receiving the greatest number of new descriptors:
| Subcat | Subcategory name | Descriptor amounts |
| B03 | Bacteria | 33 |
| B01 | Eukaryota | 30 |
| E05 | Investigative Techniques | 22 |
| F01 | Behavior and Behavior Mechanisms | 18 |
| D12 | Amino Acids, Peptides, and Proteins | 15 |
| N06 | Environment and Public Health | 13 |
| C14 | Cardiovascular Diseases | 12 |
| D08 | Enzymes and Coenzymes | 12 |
| C23 | Pathological Conditions, Signs and Symptoms | 11 |
| I01 | Social Sciences | 11 |
New descritors per category
| DeCS/MeSH Tree categories | Descriptor amounts |
| A – Anatomy | 9 |
| B – Organisms | 69 |
| C – Diseases | 41 |
| D – Chemicals and Drugs | 32 |
| E – Analytical, Diagnostic and Therapeutic Techniques, and Equipment | 34 |
| F – Psychiatry and Psychology | 32 |
| G – Phenomena and Processes | 29 |
| H – Disciplines and Occupations | 5 |
| HP – Homeopathy | 0 |
| I – Anthropology, Education, Sociology, and Social Phenomena | 19 |
| J – Technology, Industry, and Agriculture | 16 |
| K – Humanities | 0 |
| L – Information Science | 3 |
| M – Named Groups | 4 |
| N – Health Care | 25 |
| SH – Science and Health | 1 |
| SP – Public Health | 11 |
| V – Publication Characteristics | 0 |
| VS – Sanitary Surveillance | 0 |
| Z – Geographicals | 0 |
The total is greater than the number of new descriptors because some of them occur in more than one category.
DeCS 2021 for online consultation is available through the DeCS Portal or directly from the home page of the VHL Regional Portal.
Helpful Links
For more details, please refer to these documents about the DeCS 2021 edition or the Introduction to MeSH 2021.
The complete lists of changes to the vocabulary are available on the following links:
DeCS and MeSH tree number changes
MeSH and DeCS 2021 highlights:
SARS-CoV-2 and COVID-19 related descriptors
Since January 2020, terms related to SARS-CoV-2 and COVID-19 have been created in the MeSH Supplementary Concept Records database (SCR).
As SCR has not yet been included in the DeCS, and in order to be able to index and retrieve documents with them in 2020, these two concepts were inserted as non-preferred concepts in the two closest general descriptors, that is, Betacoronavirus and Coronavirus Infections, respectively.
The creation of descriptors depends on the number of publications in which the terms appeared in titles and abstracts. In this way, for example, SCR terms are created or promoted to descriptors in DeCS/MeSH or not. For version 2021, the following 14 descriptors were created. Some of these have moved from the 2020 SCR base to the 2021 MeSH, while others are new.
Coronavirus Nucleocapsid Proteins
Coronavirus Papain-Like Proteases
Coronavirus Protease Inhibitors
Coronavirus RNA-Dependent RNA Polymerase
For more details on these and other descriptors of interest to those investigating COVID-19 and SARS-CoV-2, read the NLM technical bulletin for November-December 2020.
For more information on other descriptors updated or added to DeCS/MeSH as a result of special NLM projects click here.
Access to new data fields
In this version of DeCS, the user has access to some more existing MeSH fields:
- The unique identifier of the RDF MeSH record.
- CAS Type 1 Name of substances, that is, the systematic name assigned by the Chemical Abstracts Service (CAS) according to the nomenclature convention of the American Chemical Society.
- Registration Number: contains the Unique Ingredient Identifier (UNII) linked to the molecular structure of a chemical substance and/or descriptive information by the FDA Substance Registration System (SRS).
- Related Number of substances, that is, the registration number of salts, optical isomers or versions labeled with the isotope of the substance.
Example for the four fields above: Calcimycin
- Previous Indexing: free text field that refers to descriptors or descriptor/qualifier combinations that were used to index the concept in MEDLINE databases before creating the descriptor. Its objective is to allow users of new descriptors to find similar indexed concepts before the creation of the descriptor. Includes dates in the format (YYYY) for a single year or (YYYY-YYYY) for a range of years. It can include descriptive text that refers to a group of descriptors as “specific.” References are not currently maintained when a <DescriptorName> or <QualifierName> changes. Example: Indinavir.
- New: In the same Registration Number field, previously only for substances, DeCS/MeSH now offers access to the unique identifier of the NCBI taxonomy of organisms (txid). This is part of a 2020 project in which this code was added to SCR class 4 organisms. This project was extended this year to organisms of the 2021 DeCS/MeSH subcategories B1 to B4. Example: SARS-CoV-2. For more information, read NCBI Taxonomy Identifiers Added to MeSH.
Other pertinent articles:
MEDLINE/PubMed Year-End Processing Activities for 2021 MeSH
2021 MeSH Headings Available in the MeSH Browser
Source:
Tybaert S. MEDLINE Data Changes – 2021. NLM Tech Bull. 2010 Nov-Dec;(437):e3a. Available in: https://www.nlm.nih.gov/pubs/techbull/nd20/nd20_medline_data_changes_2021.html
Translation and adaptation: Sector de Terminologías y Clasificaciones en Salud – TCS – BIREME/OPS/OMS
Last update: May 2021
