We have defined 14 scenarios based on specific epidemiological and virological factors, including animal origin, characteristics of human cases (number and exposure context), severity signals, that are then further defined based on the presence of virus mammalian adaptation, antiviral resistance and mismatch with available pre-pandemic vaccines and/or candidate vaccine viruses. The document provides a detailed guide and a simple downloadable Excel tool for defining and scoring the different scenarios based on early triggers, promoting transparency and coherence across countries, integrating a One Health perspective, through focusing on the public health side of the response measures; it describes the baseline/escalating public health actions that should be in place/implemented to ensure a timely and effective response.

Baseline actions in surveillance, laboratory preparedness and other public health interventions should always be in place in the current epidemiological situation in the EU/EEA. If there are human cases in the EU/EEA, escalating actions will apply depending on the scenario characteristics and will be further defined according to the assessment of the risk assessment; examples of escalating actions are described for every public health domain: interventions, surveillance, laboratory preparedness and additional studies/research. This guidance aims to strengthen countries’ preparedness and capacities for the early detection and assessment of potential pandemic threats from zoonotic influenza viruses. The scenario framework is intended to inform appropriate public health actions, adaptable to evolving scientific evidence and the changing epidemiological context.

The framework is intended for EU/EEA national public health authorities, in particular those involved in preparedness plan updating, risk assessors and managers, and policy-makers in EU/EEA countries. It is also relevant to clinical and laboratory stakeholders involved in zoonotic influenza surveillance, risk communication, and outbreak response.