The International Summit on Vaccine Coding & Standards was held May 9, 2025 in Bordeaux. There vaccine code experts, immunization registry leaders, and public health professionals gathered to tackle one of the most critical challenges in immunization today—ensuring that vaccine data is accurate, interoperable, and useful across borders.

This one-day summit was a unique opportunity to collaborate, share insights, and help shape the future of vaccine coding and interoperability.

Date: May 9, 2025 Location: Radisson Blu Hotel, Bordeaux, France Event: International Summit on Vaccine Coding & Standards Hosted by: International Vaccine Codes Initiative (IVCI)

The meeting opened with a welcome and framing from Nathan Bunker. He emphasized that while vaccinations are globally recognized as life-saving, the importance of recording them accurately is often overlooked. The IVC initiative was born from this recognition—where efforts to record immunizations intersected with the technical work of Syadem and the NUVA code system.

Key accomplishments shared:

• Monthly Calls (community-building)
• IVC Website (centralized information)
• Interviews with Countries and Organizations (gathering user perspectives)
• Mapping & Metrics (technical evaluation of code systems)

To get to know the group, participants responded to live polls, revealing a wide variety of backgrounds:

• Majority had extensive experience with vaccinations.
• Many worked both nationally and internationally.
• Most were familiar with coding, but many were new to the NUVA system.

Takeaway: A well-aligned agenda with audience interest, especially around practical applications of vaccine coding, understanding NUVA, and interoperability challenges.

Speaker: François Kaag

This presentation served as a foundational moment in the day, providing attendees with a deep understanding of the purpose and structure of NUVA, and how it supports long-term vaccine data interoperability.

Origins and Evolution Syadem began building NUVA to support clinical decision support systems that needed reliable vaccine history data. Initially developed to digitize paper records in France, NUVA evolved as the team participated in EU efforts (notably EVC) and recognized the broader applicability of their work. Over time, NUVA transformed into a generalized and formalized terminology designed for global use.

Not All Code Systems Are Built for the Same Purpose François highlighted that vaccine code systems are designed with different goals—some serve short-term logistics or pharmacovigilance, while NUVA focuses on long-term conceptual retention. This is especially important for immunizations, which remain relevant for decades. NUVA fills this gap by capturing meaning that persists over time, even as vaccine products and manufacturers change.

NUVA's Core Innovation: Valences A valence in NUVA describes the functional immune response a vaccine creates, not just its pharmaceutical makeup. This concept, familiar to vaccinologists, enables a practical and clinically meaningful approach to vaccine history representation.

1. Valences support varying levels of detail (e.g., `aP`, `ap`, `Per`) to handle incomplete records.
2. Slide featured: “Hierarchical Representation of Valences” shows how valences allow progressive specificity—from general (e.g., unspecified pertussis) to precise (e.g., whole-cell pertussis).

Why Valences Matter Valences solve classification problems that confound other code systems. They make it possible to:

1. Interpret multivalent vaccines correctly.
2. Reason over vaccine histories across borders.
3. Navigate between abstract and specific concepts in a structured way.

Flat Code System, Deep Valence Structure NUVA codes themselves are flat for simplicity, but are linked to a rich valence tree that enables navigation and reasoning. This dual structure supports interoperability without sacrificing semantic clarity.

Maturity of the Model Many countries assume vaccine codes are simple lists of approved products, but soon discover gaps and inconsistencies. Mature systems, like Denmark and Canada, have moved toward full ontologies. NUVA offers an off-the-shelf pivot terminology that captures this complexity for general use.

Pivot Role of NUVA in Global Interoperability Rather than build one-off mappings between every code system, NUVA functions as a pivot terminology. Each vaccine concept in other systems is either matched to or described in terms of NUVA, and the associated valences allow logical navigation between systems.

This model shows how comprehensive and structured NUVA has become, and how it continues to grow as new vaccines and national codes are incorporated.

Attendees had many questions regarding:

• How valences are determined.
• How mappings to/from NUVA are maintained.
• How NUVA relates to SNOMED CT and other national systems.
• The potential for NUVA to serve not only as a code system but as a tool for harmonization.

A demonstration of the NUVA mapping platform was shared: [https://nuva.syadem.com/mapping](https://nuva.syadem.com/mapping)

This session clarified the unique role of NUVA as the only system explicitly designed to capture long-term immunization history in a functionally meaningful way. It laid the groundwork for subsequent technical and implementation discussions throughout the day.

Speaker: Jean-Louis Koeck

This presentation provided critical clinical context for understanding the valence model at the heart of NUVA.

• Core Definitions: Jean-Louis began by clearly defining “Vaccine” and “Antigen”—foundational concepts in immunology shared globally. While basic, these helped establish common ground for a diverse audience.
• Valence: A Functional Concept: He introduced valence as a clinically grounded abstraction that enables effective interpretation of vaccination history. Definition: The smallest functional unit of a vaccine, knowledge of which is necessary and sufficient to assess an individual’s immunization status against a specific infectious agent.
• Schedules and Language: Jean-Louis compared the French vaccination schedule with international ones, highlighting that while codes and acronyms differ (e.g., DTCaP in French vs. DTaP in English), the naming logic is consistent—lowercase letters for reduced doses, for example.
• BEXSERO Case Study: Though BEXSERO contains multiple antigens, it is represented by a single valence in NUVA, because for clinical decision-making, the protection it provides as a whole matters more than each ingredient. This underscores that valences are conceptually aligned with clinical utility, not biochemical content.
• Decomposition into Valences: Multiple examples showed how different vaccine products (e.g., BOOSTRIXTETRA, REVAXIS, INFANRIX HEXA) can be broken down into valences, allowing for comparisons and decision-making regardless of product branding or local codes.
• Valence Hierarchies: NUVA includes a structured hierarchy of valences, enabling general-to-specific reasoning. This supports:
  1. Equivalence mapping
  2. Decision support
  3. Cross-code comparison
  4. Vaccine prescription using valence labels rather than commercial product names

Valences offer a common clinical language to assess protection, regardless of which product or national code system is used. This session made clear that valences are the core bridge between vaccination data and actionable immunization guidance.

*Speakers: Suzy Roy & Peter Williams (SNOMED International)*

This presentation explained how NUVA is being integrated into the SNOMED CT ecosystem to support broader adoption and interoperability.

• SNOMED International Overview: Suzy Roy introduced SNOMED International, a non-profit standards organization that maintains the SNOMED CT clinical terminology. With 51 member countries—representing one-third of the global population—SNOMED partners with organizations around the world to expand and align healthcare terminology standards.
• What Is the NUVA Extension?: NUVA has been developed as an extension to the SNOMED CT International Edition, where each NUVA vaccine is a child of the core SNOMED concept: `787859002 |Vaccine product (medicinal product)|`.

Every NUVA concept also exists as a SNOMED concept with dual identifiers—one from NUVA, one from SNOMED CT. The NUVA valence hierarchy is used to compute a logical structure of vaccines in SNOMED.

• Technical Implementation: Peter Williams described the transformation process:
  1. NUVA RDF data (`nuva_ivci.rdf`) is imported.
  2. Each vaccine and valence is created as a SNOMED concept.
  3. Valence relationships are defined using `“is a type of”` hierarchies.
  4. Abstract vaccines are marked “sufficiently defined”; branded vaccines are marked “primitive”.
  5. SNOMED tooling is used for classification, validation, and browsing.
• Working with the Extension: He demonstrated how to query NUVA codes within SNOMED using the Expression Constraint Language (ECL). For example, you can retrieve all vaccines containing a particular valence or therapeutic role. They also showed a real-world example of FHIR coding that included both NUVA and SNOMED CT codes.
• Challenges Identified
  1. The NUVA concept of valence currently doesn’t align neatly with SNOMED CT’s concept of “has active ingredient”.
  2. No errors were reported, but over 9,000 warnings were generated—mostly related to description patterns.
  3. Some monovalent vaccines in the hierarchy incorrectly show polyvalent descendants, a known classification challenge.
• Next Steps

The team will:

1. Continue aligning attribute models between NUVA and SNOMED.
2. Finalize documentation.
3. Work on automation and better internationalization (e.g., translation).
4. Decide on a long-term production schedule for maintaining and updating the extension.

This presentation showcased how NUVA is not just interoperable with SNOMED CT—it is now being formally integrated as an extension. While some technical mismatches remain, the groundwork is laid for a collaborative and sustainable pathway to global vaccine coding harmonization.

*Speaker: Georgios Margetidis* *Notes to be added*

*Speaker: Ingrid Weindorfer, Vaccines Europe*

This presentation provided the industry perspective on how NUVA supports digital innovation in vaccine communication, especially through its integration with electronic Product Information (ePIL).

• Vaccines Europe’s Mission: As a specialized group within the European Federation of Pharmaceutical Industries and Associations (EFPIA), Vaccines Europe represents major vaccine manufacturers in Europe. Their mission is to promote innovation and recognition of life-course immunization, especially in response to evolving health challenges.

• The ePIL Project (EUVABECO): Vaccines Europe is actively involved in the electronic Product Information (ePIL) initiative, which aims to replace traditional paper leaflets with up-to-date, easily accessible digital documentation. This shift became especially urgent during COVID-19, when paper-based systems slowed cross-border vaccine distribution. ePIL supports logistics efficiency, real-time updates, and resource savings. Key documents include:
  1. Package Leaflet (PL): Patient-facing
  2. Summary of Product Characteristics (SmPC): For healthcare professionals
  3. Labelling: For packaging and handling
• NUVA's Role in ePIL Integration: NUVA serves as the linking layer between vaccination records and ePIL resources. Example resource: https://epil.euvabeco.eu. For any vaccine code captured in a patient record:
  1. The NUVA code maps to the correct ePIL.
  2. This improves coordination across borders, especially for products approved centrally or through mutual recognition.
• Structured Link Format: ePIL URLs follow a standard structure (jurisdiction, NUVA code, presentation, type, language), e.g.: `/BEL/VAC0123/1/ePIL/fr` . This enables automated updates and integration with national repositories (e.g., AFMPS in Belgium, ANSM in France, EMA database).
• Future Opportunities: Ingrid suggested that deeper integration could be achieved if:
  1. Manufacturers publish link files directly.
  2. Associations between Data Carrier Identifiers (e.g., DataMatrix codes on packaging) and ePILs are managed through NUVA.

This would allow medical records to be populated automatically with key vaccine info (e.g., code, batch number, expiry), streamlining the vaccination process and enhancing accuracy.

NUVA is already proving valuable in linking vaccination history to regulatory product information. From an industry perspective, its use in ePIL demonstrates a real-world, operational benefit of having standardized vaccine codes—and points to further potential in automation, traceability, and international coordination.

Speaker: Malin Fladvad, Uppsala Monitoring Centre

Malin Fladvad shared a global pharmacovigilance perspective and explained how WHO Drug and ISO IDMP standards contribute to vaccine tracking and terminology alignment worldwide.

• About the Uppsala Monitoring Centre (UMC): UMC is an independent, non-profit WHO Collaborating Centre for the Programme for International Drug Monitoring (PIDM). Based in Sweden, it supports over 180 member countries and maintains VigiBase, the world’s largest database of anonymized adverse event reports.
• Adverse Event Reporting and Challenges
  1. VigiBase contains 40 million+ records, including 5.8 million for COVID-19 vaccines.
  2. Reports are coded using WHODrug Global, a standardized dictionary of medicines and vaccines.
  3. Many COVID vaccine reports were vague—coded as simply “Covid”—highlighting the importance of early, precise coding.
  4. WHODrug helps normalize inconsistent names (e.g., trade vs. generic) and supports multilingual contexts.
• WHODrug Global
  1. Contains over 600,000 unique drug names from 170+ countries, including 3,000+ vaccine entries.
  2. Updated twice a year, and used in clinical trials, pharmacovigilance, and global health programs.
  3. Available via downloadable files, API, and the WHODrug Insight browser.
• Draft Mappings with NUVA: The presentation shared early mappings between WHODrug codes and NUVA valences, showing how both systems can complement each other. Example mappings included:
  1. Polio Vaccines (e.g., mOPV1, IPV)
  2. HPV Vaccines (e.g., Gardasil, Cervarix)
  3. Yellow Fever Vaccines (e.g., Amaril)
• Introduction to ISO IDMP Standards:
  1. IDMP (Identification of Medicinal Products) is a global effort to assign consistent identifiers to pharmaceutical and medicinal products.
  2. IDMP distinguishes between Pharmaceutical Products (e.g., substance-based) and Medicinal Products (e.g., commercial items).
  3. WHODrug is being aligned with IDMP to ensure better data exchange, especially in adverse event reporting and clinical trials.
• Global Collaboration via GIDWG: The Global IDMP Working Group is coordinating international implementation. Pre-production data is expected by 2026. IDMP identifiers are seen as more granular and interoperable, but WHODrug remains essential for unapproved products and early-stage trials.

UMC’s work with WHODrug, combined with ISO IDMP standards, lays the foundation for standardized vaccine identification and global data exchange. Their draft mappings with NUVA highlight how systems from different domains can collaborate to improve the accuracy and utility of vaccine data across the world.

*Speaker: Maud Delporte* *Notes to be added*

*Speaker: Alain Cimino* *Notes to be added*

*Speaker: Shannon Coleman* *Notes to be added*

*Speaker: Myriam Talantikit* *Notes to be added*

*Speaker: Timothée Doulut* *Notes to be added*

*Speaker: François Kaag* *Notes to be added*

Nathan Bunker led a forward-looking session to explore how IVC and NUVA could become self-sustaining.

Key themes from breakout and group discussion:

• There’s demand for a formal entity like IVC to exist.
• Participants saw alignment with major initiatives (e.g., HL7, SNOMED, AIRA).
• Suggested model: Not a standalone organization, but a collaborative bridge between others.
• Feedback on sustainability: IVC needs a “matchmaker” to link it with major projects.

Feedback from Menti:

• Consider operating under SNOMED as a working group.
• Focus on open community access.
• Seek philanthropic funding (e.g., Gates Foundation).
• Clarify roles, responsibilities, and value of membership if structured formally.

Closing Remarks: Despite a few early departures, the day ended with energy and optimism. Feedback was positive, and the technical direction of NUVA was affirmed. The key challenge ahead is ensuring long-term viability—through partnerships, funding, or a hosting structure that ensures continuity. As Suzy from SNOMED put it, IVC now needs a “matchmaker” to connect the right people and opportunities.

Discussion emphasized “piggybacking” IVC sessions onto existing events. Ideas included:

• October 2025 SNOMED Meeting in Antwerp (SNOMED offered hosting a small IVC group).
• AIRA National Meeting inclusion.
• HL7 or other standards meetings.

The consensus: IVC should position itself as a collaborative infrastructure partner—bridging multiple organizations working toward better vaccine interoperability.

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