For several years, the H5N1 subtype of avian influenza has dominated the attention of epidemiologists and global health authorities. In 2026, the situation has evolved in a worrying way: the virus is no longer limited to poultry, it now affects a much broader spectrum of mammals, and human cases, while still rare, are on the rise. France, like its European neighbors, is on heightened alert. Here is what we know and how our country is preparing.

What is the H5N1 virus?

H5N1 is a subtype of type A influenza virus, classically associated with wild birds and domestic poultry. First identified in humans in Hong Kong in 1997, it is known for its high lethality in humans — exceeding 50% in some contexts — even though human-to-human transmission remains extremely rare.

What distinguishes H5N1 from other animal influenzas is its ability to infect a very wide range of species: from wild ducks to seals, passing through foxes, polar bears, dairy cows, and even domestic cats. This viral plasticity is precisely what worries scientists.

The spread of the virus: an unprecedented expansion

Since 2021, H5N1 epizootics (animal epidemics) have reached an unprecedented scale. Tens of millions of poultry have been culled in Europe and North America to contain outbreaks. But what truly changed the game in 2024 and 2025 was the detection of the virus in dairy cows in the United States.

This discovery was a genuine turning point. The virus was circulating within cattle farms, sometimes without obvious symptoms in animals, and agricultural workers were infected through contact with raw milk or nasal secretions from infected cattle. While these human cases did not result in deaths in the United States, they demonstrated that the barrier between animals and humans is more permeable than previously thought.

The situation in France and Europe

In France, highly pathogenic avian influenza (HPAI) has been circulating on farms for several consecutive winters. The regions of Grand Ouest, Landes and Gers are regularly affected, with dramatic episodes for waterfowl farmers. Since 2022, the government has progressively strengthened preventive vaccination of farmed poultry, a measure welcomed by industry professionals.

On the human front, no H5N1 case has been confirmed in France to date. However, health authorities maintain active epidemiological surveillance, particularly among exposed workers (farmers, veterinarians, hunters). Wearing personal protective equipment (PPE) during interventions on suspected animals is now recommended and even mandatory in certain contexts.

Why are experts more concerned in 2026?

Several factors explain why the global alert level has risen:

• Host diversification: the more the virus circulates in diverse species, the more mutations it accumulates. Some of these mutations could, in theory, allow it to spread more easily between humans.
• Increasing human cases: according to the World Health Organization (WHO), the number of human cases recorded since 2024 exceeds totals from previous years. Most are linked to direct exposure to infected animals.
• No specific curative treatment: while antivirals like oseltamivir (Tamiflu) can alleviate symptoms, no human H5N1 vaccine is yet available at scale, although several candidates are undergoing accelerated clinical development.
• Inadequate surveillance in some regions: in resource-limited countries, the virus can circulate for a long time before being detected, increasing the risk of a critical mutation going unnoticed.

How is France preparing?

Faced with this potential risk, French authorities are not standing idle. Several lines of action have been reinforced since 2025:

The National Plan for Prevention and Response to Influenza Pandemic (PanFlu) has been updated. This plan provides notably for the constitution of strategic antiviral stockpiles, the capacity to rapidly produce a vaccine adapted to a new pandemic influenza strain, and the establishment of a clear health command chain in the event of an outbreak.

Furthermore, the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) regularly publishes risk assessments, while Public Health France coordinates human surveillance. Hospitals have been sensitized to managing suspected cases, with enhanced isolation protocols.

What is the real risk for the French population?

It is important to distinguish the current real risk from the hypothetical future risk. Today, the risk for the general population is very low. The H5N1 virus does not spread easily between humans. An ordinary person, without contact with infected animals, has a near-zero probability of being contaminated.

However, if the virus were to acquire the ability to transmit efficiently from person to person — a scenario virologists call "pandemic adaptation" — the picture would change radically. It is precisely this low-probability but high-impact risk that justifies current preventive investments.

"We cannot afford to wait for a pandemic virus to appear before starting to organize. Preparation must happen well in advance." — Joint position of WHO and ECDC experts, 2025

What each person can do

For the general public, recommendations remain commonsense:

• Do not touch dead or sick wild birds, and report them to authorities (departmental veterinary services or regional food directorate).
• Avoid consuming raw milk or unpasteurized dairy products from at-risk areas.
• Wash hands regularly, especially after any contact with farm animals.
• Report any unusual flu-like symptoms occurring in the days following contact with poultry or other suspected animals.

For professionals in regular contact with animals, wearing PPE (FFP2 mask, goggles, gloves) is essential when intervening on potentially infected animals or in affected farms.

Conclusion: vigilance without alarmism

H5N1 avian flu represents a serious threat to monitor, but not yet an immediate threat to the French population. The key lies in continuous surveillance, proactive preparation and transparency of communication between scientists, authorities and citizens. In 2026, France has solid monitoring and response mechanisms — the result of lessons learned from the Covid-19 pandemic and previous avian crises.

The challenge now is to maintain this vigilance over time, without yielding to either panic or complacency. For with influenza viruses, the question is often not if a pandemic will occur, but when and in what form.