A risk level assessed as “low” for the general public

The highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype has been circulating extensively worldwide for several years, primarily among wild birds (such as ducks and geese) and domestic poultry (chickens, ducks, turkeys). It is also capable of infecting numerous species of wild mammals (foxes, seals, sea lions, etc.) and domestic animals (cats, dogs, pigs). This virus has also been detected for the first time in dairy cows in the United States. The virus can occasionally be transmitted to humans, in which case it is referred to as avian influenza. In this regard, the international situation is concerning, particularly in the United States, but no human-to-human transmission has been observed to date. In France, no human cases of avian influenza have been detected so far.

Thus, while the risk to human health is assessed as “low” by the World Health Organization (WHO) and the European Centre for Disease Prevention and Control (ECDC), it is assessed as “low to moderate” for those most at risk, particularly people working in poultry farms.

Coordinated action by human and animal health authorities

As part of a “One Health” approach based on the interdependencies between human health, animal health, and environmental health—to develop new methods for disease surveillance and control—human and animal health authorities have been coordinating their efforts for several years to ensure effective monitoring of the circulation of these viruses in animals and humans, detect any transmission to a new species, and respond rapidly to potential human cases.

Working in close coordination, the authorities have implemented several preventive and management measures, including:

• Raising awareness among professionals exposed to the risk as part of their work (livestock farmers, livestock technicians, veterinarians, etc.) regarding preventive and protective measures for their farms, as well as vaccination against seasonal influenza, to prevent an animal-origin influenza virus from recombining with a human influenza virus and becoming more pathogenic to humans. Healthcare professionals have also been educated to inform them of the appropriate course of action.

• To improve our ability to detect human cases of influenza of animal origin early, PCR tests for diagnosing seasonal influenza are now covered year-round for those most at risk who exhibit symptoms.

• A pilot program for active surveillance of avian influenza (SAGA) has also been implemented among individuals exposed in poultry farms and will enable earlier detection of the disease and the implementation of appropriate management measures.

• Mandatory vaccination of ducks, implemented since October 2023, has proven to be a major collective success, with nearly 62 million ducks vaccinated and a drastic reduction in the number of HPAI outbreaks in France (only about ten HPAI outbreaks detected on farms in France in 2023/24, compared to approximately 400 each year before vaccination, with a peak of nearly 1,400 outbreaks in 2021/22). This strategy is being continued for the 2024/2025 season. Fewer outbreaks on farms mean a lower risk of infection among workers and a lower risk of transmission to the general population.

• Enhanced surveillance of the health status of domestic poultry and wild birds.

In addition, a pandemic preparedness strategy is being implemented, including:

1. The establishment of vaccine stockpiles for individuals who may have come into contact with a sick person or animal should a virus become transmissible to humans

2. Pre-ordering vaccines in anticipation of an influenza pandemic

3. The stockpiling of antiviral medications effective for symptomatic patients

4. Preparation of the healthcare system through operational health planning (ORSAN) to address the impact on healthcare provision

What are the symptoms, and what should you do if exposed?

In the event of exposure to infected animals or a contaminated environment (farmers, livestock technicians, veterinarians, etc.) and if symptoms appear (even mild ones, such as fever, headaches, muscle aches, cough, shortness of breath, or conjunctivitis), it is recommended to monitor your health for 10 days and to:

• Immediately contact a doctor, specifying that you have been in contact with infected or suspected animals, so that they can prescribe a PCR test;

• Follow preventive measures: wear a mask, wash your hands frequently, ventilate rooms regularly, disinfect surfaces, etc.