Avian influenza (bird flu)
Avian influenza, also known as bird flu, is a viral disease that can be highly pathogenic in birds. Highly pathogenic avian influenza is a serious threat to birds that can have economic consequences for poultry farmers across the world, including in the European Union (EU). Although the public health risk is low, the European Medicines Agency (EMA) works with public health authorities in the EU and worldwide to monitor the risk and prepare to respond to a potential public health emergency.
Avian influenza is a highly contagious viral disease that occurs mainly in poultry, such as chickens, ducks and turkeys and wild water birds, such as gulls. It can affect both wild and farmed (domestic) birds.
Some strains of avian influenza can be highly pathogenic, meaning that infected birds can suffer serious disease or even death.
Outbreaks of avian influenza have occurred in the EU since the early 2000's. However, 2021 and 2022 saw the highest number of outbreaks of highly pathogenic virus ever recorded in Europe, particularly in farmed poultry. Recent data show high infection rates of highly pathogenic virus in several regions of the world, which have made it necessary to cull an extensive number of farmed birds.
Certain mutations may allow the virus to spread from mammal to mammal, which makes it of particular concern.
There is no evidence the virus can be transmitted to humans through food, such as contaminated poultry products. However, poultry workers, veterinarians and other people in direct contact with infected birds are at increased risk of infection.
While the public health risk remains low, authorities such as EMA must be alert to the risk of a potential outbreak affecting humans as well as birds.
More information on avian influenza is available from the European Food Safety Authority (EFSA), European Centre for Disease prevention and Control (ECDC) and European Commission:
EMA oversees the evaluation and supervision of medicines for both humans and animals in the EU.
EMA is therefore responsible for evaluating potential vaccines to protect birds against the virus, and potential vaccines and treatments for humans.
It also has a role in preparing for and managing crisis situations affecting the EU, based on legislation that took effect on 1 March 2022.
In the EU, the European Food Safety Authority (EFSA) is responsible for monitoring data on diseases caused by infections that spread between animals and people (zoonotic diseases) in cooperation with the European Centre for Disease prevention and Control (ECDC) and EU Member States.
There is currently one veterinary vaccine authorised in the EU for the prevention of avian influenza A, subtype H5, in chickens:
This is a conventional, inactivated vaccine, which could potentially help address the risk of highly pathogenic avian influenza, but it is currently produced in limited quantities.
Several other vaccine candidates are currently at different stages of development.
Farmed poultry are not routinely vaccinated against avian influenza in the EU. However, the European Commission has asked EFSA to provide a scientific opinion on possible vaccination and monitoring strategies in Europe. For more information see:
Vaccination against highly pathogenic avian influenza is common in some regions outside the EU. Several vaccines are thus available, although not currently authorised in the EU. EMA ran a survey in February 2023 to gather relevant information on these vaccines and offered to discuss EU authorisation with their manufacturers.
EMA is in dialogue with medicine developers to gain an overview of available data on suitability of existing and potential new vaccines and treatments, and opportunities to adapt existing vaccines to match more closely the virus strains in circulation, in readiness to respond to the public health threat. EMA's Emergency Task Force (ETF) is reviewing all the available information.
If necessary, EMA can trigger its plan for Public health threats, which guides how EMA operates during an emerging health threat, where increased speed, efficiency and coordination among public health authorities are critical.
The plan enables fast-track approval of vaccines and antivirals to prevent or treat a disease caused by an emerging virus. It also allows EMA to mobilise and concentrate scientific resources across the European medicines regulatory network in response to a threat.
One vaccine is authorised for use in the EU during avian influenza outbreaks without there being a declared pandemic, including to protect poultry workers, veterinarians and other people at increased risk of exposure. It might need adapting to match more closely the current virus strains:
There are four pandemic preparedness influenza vaccines authorised in the EU that can be rapidly modified to protect people in a pandemic situation:
- Pandemic influenza vaccine H5N1 AstraZeneca (previously Pandemic influenza vaccine H5N1 Medimmune)
- Pandemic Influenza Vaccine H5N1 Baxter AG
- Adjupanrix (previously Pandemic influenza vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals)
These were authorised based on immunogenicity data. They can be adapted to protect against any pandemic influenza virus strain if necessary.
They are only for use if the WHO or the EU were to officially declare a pandemic, which has not happened.
Certain antiviral medicines are also authorised for use in the EU to treat influenza: