Avian Influenza and Swine Flu: Europe Adopts a “Pre-Pandemic” Action Plan

The ECDC has published an operational framework with fourteen scenarios to provide real-time guidance for member states’ responses to the risk of an influenza A (H5N1) pandemic and other animal-origin influenza outbreaks. As highly pathogenic H5N1 avian influenza is circulating at unprecedented levels among wild birds in Europe, European public health experts are working to prepare a response even before the first human case occurs. The ECDC has just published an operational framework designed to help countries in the European Union and the European Economic Area (EEA) to address avian influenza or swine flu in humans, whether caused by avian viruses such as H5N1 or viruses of swine origin. The purpose of this document is not to predict the date of the next pandemic, but to standardize the response to even subtle warning signs: the emergence of an isolated case, the occurrence of a small family cluster, the detection of mutations suggesting better adaptation to mammals, or early indications of resistance to antivirals or the ineffectiveness of available vaccines. These are all situations in which a delay of just a few days can have serious consequences for the course of events.  

Fourteen “pre-pandemic” scenarios

The action plan developed by the ECDC is based on fourteen so-called pre-pandemic scenarios. Each scenario combines several parameters:

• the animal origin of the virus in question;
• the number of reported human cases and their context (no cases, sporadic cases, localized outbreaks);
• the degree to which exposure to infected animals has been established;
• indicators of severity, adaptation to mammals, resistance to antivirals, or antigenic drift relative to the antigens targeted by potential preventive vaccines.

The current situation in Europe serves as a starting point. No human cases linked to influenza viruses have been reported there so far, but H5N1 is circulating widely among wild birds, and outbreaks still occur regularly in poultry farms. This is the baseline against which Member States are asked to conduct a self-assessment: the capacity of surveillance systems to detect unusual signs, the availability of virological tests, the existence of antiviral stockpiles, the clarity of the decision-making chain, and coordination with animal health services. As soon as the first human case occurs in the European Union or the EEA, the scenario changes in nature. We then enter situations of emergence or introduction, where a decision must be made as to whether the event remains strictly linked to animal exposure or whether it suggests the onset of human-to-human transmission. As the number of cases increases, outbreaks multiply, and concerning virological findings emerge, the framework provides for a gradual escalation of the response.  

A Practical Guide for Public Health Authorities

One of the key strengths of this tool is its operational focus. For each scenario, the document first outlines what must be in place at all times: syndromic and virological surveillance capable of detecting unusual cases, laboratories trained in the use of specific tests for avian or swine viruses, and data-sharing networks between regions and countries. It then describes the additional measures to be activated when a threshold is crossed. In terms of surveillance, this may involve expanding testing criteria in certain emergency departments or at primary care physicians’ offices, increasing the frequency of genomics sequencing, or linking data from human and animal health in near real time. On the laboratory side, the ECDC emphasizes the ability to scale up rapidly: availability of reagents, control panels, RT-PCR platforms adapted to specific subtypes, systems for submitting and analyzing genomes through international databases, etc. The document also addresses the protection of exposed workers. These include, in particular, livestock farmers, veterinarians, slaughterhouse staff, personnel responsible for collecting wild animal carcasses, and employees responding to avian outbreaks. The text outlines the principles of targeted medical surveillance for these groups and considers, in certain advanced scenarios, the prophylactic use of antiviral drugs. Regarding risk communication, the ECDC emphasizes the need for clarity: the goal is to explain the situation without downplaying or exaggerating it, to update messages as the situation evolves from one scenario to another, and to maintain constant dialogue with healthcare professionals, the agricultural sector, and the general public. It is recommended to prepare statements in advance rather than improvising during a crisis.  

Preparation Based on the One Health Approach

This operational framework builds on the work carried out jointly in recent years by the ECDC, the European Food Safety Authority (EFSA), and the European Medicines Agency (EMA) on the zoonotic risk posed by avian influenza viruses, vaccination strategies in livestock operations, and integrated surveillance at the interfaces between wildlife, livestock, and human populations. From the outset, the approach adopted is the One Health approach. The circulation of the virus among wild birds, poultry, pigs, or other mammals is not considered peripheral information, but rather a prerequisite for assessing the risk to humans. The document encourages joint investigations during avian outbreaks deemed to be of concern: rapid identification of exposed individuals, establishment of testing protocols for relevant healthcare professionals, and coordination of genomics analyses between veterinary and human health laboratories. The framework also addresses the possibility of using so-called pre-pandemic vaccines in targeted groups of workers when certain virological indicators are present and appropriate products are available. The idea is not to launch massive campaigns based on assumptions, but to avoid finding ourselves—due to a lack of prior planning—in a situation of total improvisation if a virus of avian or swine origin becomes more transmissible among humans.  

A Warning Without Alarmism

For Edoardo Colzani, a specialist in respiratory viruses at the ECDC, the key message is that the risk to the general population in Europe remains low at this time, but that it would be unwise to rely on luck. The probability of sporadic human cases linked to H5N1 or another animal influenza virus emerging at some point is not zero, given the intensity of viral circulation among animals. The challenge, the agency reiterates, is not to miss early warning signs, as was the case at the start of the COVID-19 pandemic. This pre-pandemic framework is primarily intended for national authorities, health agencies, and national reference laboratories, but its implications extend beyond this circle. It foreshadows decisions that could affect daily life: targeted strengthening of surveillance in a particular region, specific recommendations for certain professions, organizing the distribution of antivirals to specific groups, or even discussions about limiting vaccination to frontline workers. By making this tool public and detailing the scenarios under consideration, the ECDC is committed to transparency and preparedness. In a context where rumors of an “imminent new pandemic” spread easily, the goal is to show that the discussion is neither limited to denial nor to constant alarm, but rather involves patient, methodical planning.  

Anticipate Rather Than React

As the H5N1 virus becomes firmly established in the wildlife populations of several continents and new mammalian hosts are regularly discovered, Europe is attempting to address a shortcoming that was often highlighted during previous crises. By defining scenarios and graduated responses in advance, Europe hopes to avoid a repeat of the sense of improvisation that characterized the first months of 2020. This framework will not prevent the emergence of an avian or swine influenza virus capable of crossing the species barrier, but it can help bring the situation under better control when the time comes, as the appropriate response will no longer depend solely on a few individuals, but on a plan that has been carefully thought out and prepared in advance.