The first in-person meeting of the International Vaccine Code (IVC) Initiative was held in Bordeaux, bringing together experts from across Europe and Americas to explore the technical, clinical, and operational challenges of vaccine coding. With over 35 participants attending both in person and online, the event marked a major milestone in building a collaborative global community focused on improving how vaccinations are digitally recorded and shared.

The meeting opened with a review of IVC's goals and accomplishments so far, including monthly calls, the launch of the IVC website, interviews with countries and organizations, and work on mapping and metrics. Participants shared their backgrounds and expectations through an interactive poll, revealing a wide range of experience levels and strong interest in improving global harmonization, tracking vaccine histories, and understanding the role of NUVA—a terminology developed by SYADEM—as a pivot code system for vaccines.

The core of the meeting focused on in-depth presentations about NUVA and its integration into systems like SNOMED CT, WHO Drug, national registries, and EU projects such as ePIL and the European Vaccination Card (EVC). Real-world use cases from Luxembourg, Canada, the U.S., and Qatar demonstrated the challenges of managing and reconciling vaccine data across fragmented systems. NUVA’s conceptual framework of valences emerged as a unifying method for linking diverse codes and improving clinical decision support.

Toward the end of the meeting, discussions shifted to sustainability and future governance. Participants debated the pros and cons of forming a formal organization versus aligning with existing structures like SNOMED or HL7. While no final decision was made, there was strong consensus that IVC fills a unique gap and that its work should be nurtured through partnerships and “matchmaking” with larger efforts already underway.

The energy and feedback from participants confirmed that this work is both needed and technically on the right track. Moving forward, the IVC Initiative will focus on expanding its community, deepening partnerships, and continuing to serve as a bridge between technical solutions and public health realities in the field of immunization.

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.

FOUNDATIONS AND GLOBAL PERSPECTIVES

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

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 (Syadem)

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.

REAL-WORD USE CASES - GLOBAL AND EUROPEAN UNION

Speaker: Georgios Margetidis, Health and Digital European Agency (HaDEA)

Georgios presented the frame for the European Commission (EC) actions in the field of digital health.

According to the European treaties, health is a national competence of Member States. Apart from specific cases regarding cross-border continuity of care, the EC actions can only be incentives. This has been achieved so far through studies, recommendations, joint actions and voluntary groups.

The European Health Data Space (EHDS) regulation, published in March 2025, creates a new context for digital health, with the obligation for Member States to progressively build up interoperability across electronic health records both for primary and secondary use of data.

An harmonized approach for recording administered vaccines would be a significant contribution to this objective. Patient summaries, including vaccination history, should be exchangeable across all Member States by March 2029.

The EHDS regulation allows the EC to become prescriptive on interoperability.

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.

REAL-WORK USE CASES - COUNTRIES

Speaker: Maud Delporte (Agence eSanté Luxembourg)

Maud Delporte shared the ongoing efforts in Luxembourg to digitize and centralize vaccine histories through the Carnet de Vaccination Électronique (CVE)—a national immunization registry built with NUVA at its core.

• What is CVE?: The CVE is Luxembourg’s national system for digital vaccination records. It should not be confused with EVC (Electronic Vaccine Card), though it may serve as its foundation in the future. CVE records are centralized and integrated into the national health document repository (DSP).
• Adoption and Participation: The program is voluntary, but participation is growing rapidly:
  1. 58,000 digital records after just one year.
  2. Population: ~666,000.
  3. Growth rate: ~3% per month.
• Workflow Integration and NUVA Usage
  1. Vaccine boxes are scanned using Datamatrix codes, which capture the GTIN and link it directly to a NUVA code.
  2. This enables traceability from vaccine delivery to administration.
  3. NUVA-powered drug data flow supports automatic vaccination registration.
• Clinical Decision Support Integration
  1. The system supports decision support by linking administered vaccines to valences.
  2. This allows for dose tracking, eligibility reminders, and clinical auditing.
• Forward-Looking Plans
  1. CVE will evolve into a full EVC for Luxembourg.
  2. Plans to integrate CVE with Luxembourg’s national drug database.
  3. This opens the door for future ePrescription and deeper interoperability with European vaccine systems.

Luxembourg’s CVE initiative is a model of practical, NUVA-based vaccine data management. It shows how even a small country can build a scalable, standards-based digital immunization registry with clinical and logistical value.

Speaker: Alain Cimino (Cimbiose)

This session introduced the broader European effort to develop and pilot the Electronic Vaccination Card (EVC) as part of the EUVABECO initiative, a post-pandemic collaboration across nine countries.

• Background and Origins: The EVC concept was already under development before COVID-19, but the pandemic accelerated its relevance and scope.
  1. A 2018 EU Council Recommendation prompted exploration of a shared vaccination card.
  2. The EUVABECO project emerged from follow-up research to develop practical tools for implementation, not just policy.
• Project Structure and Scope
  1. 15 partners from 9 countries
  2. 18 pilot projects running from Jan 2024 to June 2026
  3. €8.4M total budget
  4. Applies a structured industrial V-Cycle process: Verify and Validate
• Five Pre-Selected Tools
  1. Forecasting Tool – Predict outcomes of vaccination programs.
  2. Data Linkage System – Identify and reach vulnerable populations.
  3. Clinical Decision Support (CDS) – Personalized vaccine guidance.
  4. ePIL (Electronic Patient Information Leaflet) – Improve cross-border product understanding.
  5. EVC (Electronic Vaccination Card) – A portable digital and human-readable vaccination record.
• About the EVC
  1. Designed to be decentralized and interoperable across EU Member States.
  2. Comes in two formats:
     1. Human-readable (for individuals)
     2. Digitally readable (by apps and health systems)
  3. NUVA is embedded in the QR code to standardize vaccine representation and enable cross-border understanding.
  4. Supports deduplication, record reconciliation, and continuity of care across Europe.
• Pilots for EVC
  1. Currently underway in Belgium, Germany, Greece, and Latvia.
  2. EVC is being integrated into national Immunization Information Systems (IIS).
  3. Pilots are testing reading and reconciliation of vaccine history across borders.
• Future Outlook
  1. Project deliverables (like EVC specifications and tooling) will become EU public goods.
  2. NUVA is positioned as a long-term framework for vaccine code mapping and standardization.

The EVC, supported by the EUVABECO consortium, is shaping up to be a cornerstone of EU vaccine interoperability. With NUVA embedded at its core, this project not only strengthens citizen access and trust but also lays the groundwork for seamless data-driven vaccination care across Europe.

Speaker: Shannon Coleman (STCHealth)

Shannon Coleman provided a comprehensive overview of vaccine coding practices and challenges in North America, drawing from her experience at STCHealth—a software vendor and integrator supporting immunization data exchange across various sectors.

• STCHealth’s Role: STCHealth operates across the U.S. healthcare ecosystem—from public health agencies to payers, providers, and employers. They support Immunization Information Systems (IIS) and health data exchange nationally and internationally.
• Vaccine Code Systems in the U.S.: Shannon outlined several coding systems commonly used in the U.S. Each plays a role in recording, billing, and reporting—but integrating them smoothly remains a challenge:
  1. CVX (Vaccines Administered)
  2. MVX (Manufacturer Codes)
  3. NDC (National Drug Codes)
  4. CPT (Current Procedural Terminology)

• The Code Creation Pipeline: A key highlight was how complex the process is to establish and disseminate a new vaccine code:
  1. One diagram showed the approval and creation pipeline for CVX/NDC codes.
  2. Another diagram illustrated the adoption process, revealing multiple layers of system updates, testing, and communication that are often underestimated.

• IIS Code Management Realities: Shannon explained that even after a code is published, it needs to be manually entered or synchronized into various parts of an IIS. STCHealth sees three main update models:
  1. Manual – Fully dependent on staff entry.
  2. Hybrid – Partially automated with staff validation.
  3. Service-Based – Centralized services update local systems.

• IZ Gateway: The IZ Gateway initiative is helping improve interoperability among U.S. state IISs. However, it still faces limitations, especially in handling non-U.S. vaccine codes in global contexts.

• International Use Case: Qatar: Shannon shared STCHealth’s experience in Qatar, where their system had to be adapted to support non-U.S. vaccines. This highlighted the U.S.-centric design of many current tools and underscored the need for more globally adaptable code frameworks.

• Looking Ahead: Key recommendations and areas of focus:
  1. Improve internal coordination and tooling for managing vaccine codes.
  2. Enhance national release mechanisms for vaccine codes from CDC.
  3. Create guidance documents and dictionaries to define key terms and concepts for more consistent implementations.

This session demonstrated the technical complexity and operational reality of managing vaccine codes in the U.S. It also showed how experiences from international deployments (like Qatar) reveal the need for globally harmonized coding systems—something initiatives like NUVA can help support.

Speaker: Myriam Talantikit (Canada Health Infoway)

This presentation provided an overview of how vaccine data is standardized, coded, and shared across Canada, with emphasis on the current systems in place, recent progress, and remaining challenges.

• Canada Health Infoway (CHI): CHI is a national, independent, not-for-profit organization established in 2001. It leads digital health innovation in Canada and supports the Canadian Standards Release Centre (CSRC), which maintains SNOMED CT CA and other terminologies.
• Decentralized Immunization Registries
  1. Canada does not have a national immunization registry.
  2. Each Province and Territory (P/T) maintains its own system, with exceptions in places like Nunavut (no registry) and Northwest Territories (uses EMRs).
  3. These registries are confidential and population-based.

• National Vaccine Catalogue (NVC)
  1. Serves as the central repository of vaccine information in Canada.
  2. Leverages SNOMED CT CA and integrates with other terminologies like DIN, lot numbers, and expiry dates.
  3. Supported by a national terminology server that offers consistent terminology access.

• National Terminology Service (NTS)
  1. Provides access to a wide range of terminologies including SNOMED CT CA, LOINC, pCLOCD, UCUM, and others.
  2. Benefits include:
     1. Centralized access, frequent updates, and FHIR compatibility.
     2. Improved semantic interoperability across systems.
     3. Tools for concept mapping, validation, and expansion.

• Pan-Canadian Health Data Content Framework (pCHDCF)
  1. Developed by CIHI to standardize person-centric data across care settings.
  2. Focuses on data modeling, semantic consistency, and aligning national priorities.
  3. Serves as the foundation for national interoperability efforts.

• Pan-Canadian Patient Summary (PS-CA)
  1. A localized implementation of the International Patient Summary (IPS).
  2. Built using HL7 FHIR profiles, it enables portable and shareable patient summaries across Canadian jurisdictions.
  3. Actively developed in collaboration with provincial stakeholders.

• Successes:
  1. Rapid support and adoption for COVID-19 vaccine codes.
  2. National RFC (Request For Change) process in place.
  3. Strong alignment between NVC and CHI terminologies.

• Challenges:
  1. Outdated and local terminologies persist in some jurisdictions.
  2. High barrier to SNOMED adoption for smaller organizations.
  3. Complexity in managing thousands of terminology copies.
  4. Some legacy tools like patient picklists are underutilized or outdated.

• Discussion on Canadian Vaccine Catalogue (CVC)
  1. During Q&A, participants asked about the now-discontinued CVC previously managed by CanImmunize.
  2. While the CVC was previously compared with NUVA, it is no longer in use and considered outdated in current Canadian practice.

Canada’s vaccine coding landscape is evolving, with strong national leadership in terminology and standards through CHI. Despite the decentralized registry model, shared tools like the NVC, national terminology server, and PS-CA are improving interoperability and standardization—laying a foundation for long-term digital immunization strategies.

IMPLEMENTING NUVA FOR INTEROPERABILITY

Speaker: Timothée Doulut (SYADEM)

Timothée Doulut demonstrated how the NUVA system supports cross-mapping between various vaccine coding systems, using valences as the unifying conceptual anchor.

• From Valences to Vaccines: Timothée walked through the process of mapping a vaccine code by first identifying its valences—the smallest functional units that describe immune response.

Once valences are known, the NUVA system can identify the corresponding vaccine codes.

• Mapping Tools at nuva.syadem.com: A web-based mapping tool was showcased, where users can input existing codes (e.g., CVX, ATC, CIP, CNK, CTI) and retrieve:
  1. NUVA vaccine codes
  2. Associated valences
  3. Brand or abstract vaccine concepts

• The system supports both:
  1. Direct mapping (e.g., a specific product like PRIORIX)
  2. Indirect mapping via shared valences (e.g., DTaP/Hib combinations)

• Handling Missing or New Concepts: If an external code has no match in NUVA:
  1. It is assessed by reviewing disease coverage, product name, dose, and formulation.
  2. If new valences are needed, they are created.
  3. If the vaccine is already covered by existing valences, a new vaccine concept is added using those valences.

• Decision-Making Process: Mapping a new code into NUVA involves multiple steps:
  1. Determine if the code is abstract or concrete.
  2. Identify associated diseases and valences.
  3. Evaluate whether to reuse or create a concept.

• The goal is always to preserve semantic precision while supporting practical interoperability.

• Terminology Sensitivities: “Generic” Vaccines : One key discussion point came from the use of the term “generic vaccine” in the slides.
  1. Intended meaning: a generalized vaccine concept not tied to a specific product.
  2. However, participants from the vaccine manufacturing sector noted that “generic” implies non-branded biosimilar drugs, which do not yet exist for vaccines.
  3. Outcome: The group agreed to avoid using “generic” in future presentations to prevent confusion and respect established pharmaceutical terminology.

This session highlighted how NUVA’s valence-driven approach supports efficient and scalable mapping across multiple vaccine coding systems. The demonstration of the mapping tool and discussion around concept management illustrated how NUVA is built to bridge gaps between fragmented code systems, while adapting respectfully to stakeholder language and expectations.

Speaker: François Kaag (IVCI/SYADEM)

François Kaag introduced a method for using NUVA to generate metrics that evaluate the completeness, precision, and redundancy of other vaccine coding systems. These metrics can help developers understand the strengths and limitations of their systems and support better cross-system alignment.

• Abstract vs. Concrete Vaccines: François clarified the terminology around abstract vaccines—concepts that describe the vaccine type or valence structure without referring to a branded product. Examples:
  1. “Polio” is a higher-level abstract concept.
  2. “IPV” and “OPV” are more specific abstract vaccines.
  3. Branded vaccines like “Infanrix” or “Gardasil” are concrete vaccines.
• He introduced the “abstraction cone”, a visual tool showing how vaccine concepts range from general to highly specific. This supports reasoning about what kinds of vaccine data a coding system can capture.
• Completeness and Precision Metrics: NUVA can be used to compare how well other coding systems:
  1. Completeness: Cover the full range of vaccine concepts in NUVA.
  2. Precision: Distinguish between similar concepts without ambiguity.
• Example findings:
  1. CVX covers 88% of NUVA concepts with 82% precision.
  2. ATC covers 83%, but precision is only 71%.
  3. CVC is lower on both measures.
  4. CNK has very low completeness and high ambiguity (precision not calculated).
• Redundancy

Redundancy measures how many codes in an external system map to the same NUVA concept. This isn’t necessarily a flaw—it often reflects the external system's inclusion of other dimensions (e.g., packaging, administration form).

• Example:
  1. CVX-120 and CVX-170 both map to the same NUVA concept (DTaP/IPV/HIB vaccine), differing only by geographic usage.
  2. CNK codes include both flask and syringe presentations for the same vaccine.
• Tooling and Results: A Python script (`NUVA_Eval.py`) was introduced to calculate these metrics.
  1. Input: a CSV mapping file.
  2. Output: metrics for completeness, precision, and redundancy.
  3. Reference materials and code are available at: https://ivci.org/nuva
• Interpreting the Metrics: These metrics are not absolute quality scores—they must be interpreted based on the intended purpose of the code system:
  1. A code system may be highly complete but imprecise (e.g., a generic “Any Vaccine” code).
  2. Conversely, pharmaceutical databases may be highly precise but unable to represent historical or abstract vaccination records.

NUVA provides a structured way to evaluate and compare vaccine coding systems. By analyzing how abstract and concrete vaccine concepts are covered and differentiated, François offered a valuable toolset for improving the interoperability and quality of vaccine terminology across countries and organizations.

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 one participant 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.