欧洲疾控中心-大流行前人畜共患流感防备和应对方案（英）-2025.12_71页_3mb

ECDC Guide and Tools: Scenarios for Pre-Pandemic Zoonotic Influenza Preparedness and Response in the EU/EEA

Core Content

This report by the European Centre for Disease Prevention and Control (ECDC) outlines a scenario-based framework to guide scalable public health responses to zoonotic influenza threats in the EU/EEA. The framework is designed to support early detection, assessment, and response to potential pandemic threats from zoonotic influenza viruses, particularly A(H5N1), and to align national actions with a One Health approach.

Main Points

• Purpose: To provide a structured approach for public health preparedness and response to zoonotic influenza viruses with pandemic potential.
• Context: The document was developed in response to the unprecedented circulation of HPAI A(H5N1) in wild birds across Europe during the 2025 autumn migration, as reported by EFSA.
• Target Audience: EU/EEA national public health authorities, risk assessors, policy-makers, and clinical/laboratory stakeholders involved in zoonotic influenza surveillance and outbreak response.
• Scope: Focuses on pre-pandemic scenarios, not pandemic-phase planning. It does not cover animal health measures to mitigate importation risks, which are addressed in other documents.

Key Scenarios and Actions

The framework defines 14 scenarios based on the following factors:

1. Animal origin (birds, mammals)
2. Case and exposure context (number of cases, clustering, known/unknown exposure)
3. Severity signals
4. Genetic markers for mammalian adaptation (subcategories A and B)
5. Limitations in pharmaceutical measures (antiviral resistance -R, vaccine mismatch -V)

For each scenario, the document outlines baseline and escalating public health actions, including:

• Case and contact management
• Surveillance and outbreak investigations
• Laboratory preparedness and diagnostics
• Risk communication and training
• Occupational health and safety measures
• Infection prevention and control (IPC)
• Antiviral and vaccination strategies
• One Health coordination and international collaboration

Key Considerations

• The scoring system accounts for increased concern, such as:
  • Virus origin in mammals or unknown sources
  • Unknown exposure
  • Clusters of cases
  • Severe infections
  • Genetic markers indicating mammalian adaptation
• Public health actions must be adaptable based on evolving scientific evidence and epidemiological context.
• A precautionary approach is recommended when uncertainty exists, especially regarding mammalian adaptation and potential human-to-human transmission.
• Heightened alert actions may be triggered for scenarios outside the EU/EEA if they involve mammalian adaptation or signals of human-to-human transmission.

One Health Approach

A coordinated One Health strategy is essential for responding to zoonotic influenza. The framework is complementary to the ECDC/EFSA One Health guidance [5], which outlines the triggers and organisation of joint investigations. The current document defines which public health actions to escalate based on the outcomes of these investigations.

Scenario Scoring System

• A composite algorithm is used to score scenarios based on:
  • Onward human-to-human transmission potential
  • Virological adaptation to mammals
  • Severity potential
• The total scenario score ranges from 0 to 15, with higher scores indicating greater public health concern.
• Two qualitative modifiers (-R for antiviral resistance, -V for vaccine mismatch) are included but do not contribute numerically to the score.
• The scoring system was validated using real-world cases and stress-tested to ensure differentiation between scenario levels.
• The scoring system is not intended to estimate the likelihood of a pandemic but to guide timely and proportionate response actions.

Tools and Resources

• A downloadable Excel tool is provided to support scenario definition and scoring.
• Annexes include:
  • Scenario scoring and definitions
  • List of national baseline and escalating actions with relevant resources
  • National-level escalating actions for each scenario
  • Mammalian adaptation traits identified by ECDC/EFSA
  • Case study illustrating the framework in practice

Conclusion

This guide promotes transparency, coherence, and early action across the EU/EEA by providing a structured framework for scenario-based preparedness and response. It supports national and supranational coordination, integrates a One Health perspective, and aligns with EU regulations and international guidance such as WHO and CDC tools.