Vaccination of birds against high pathogenicity avian influenza (bird flu) joint statement from the avian influenza vaccination taskforce
11 March 2025
Since October 2021 an unprecedented number of high pathogenicity avian influenza (HPAI) outbreaks have been reported throughout Europe and in many regions of the world.
The impact of HPAI on poultry producers is significant, which is why we continue to reiterate the importance of robust biosecurity measures. Where disease occurs, early reporting, rapid diagnosis, and robust disease control measures help to minimise the spread of disease and mitigate its effects on the wider poultry industry.
These control measures include movement restrictions, culling and disposal, cleansing and disinfection, epidemiological investigations and surveillance.
1. Current HPAI vaccination policy
The current UK policy on vaccination to protect birds against HPAI is not to permit the vaccination of birds (outside of zoos in England and Northern Ireland) either for disease prevention or as a disease control response.
While preventative vaccination in poultry is recognised as a potential disease control measure and authorised H5 specific vaccines are available in the UK (Nobilis Influenza H5N2 which has marketing authorisations which could allow its use in Great Britain and Northern Ireland, and Innovax-ND-H5 which is authorised throughout the EU and according to the Windsor Framework could be marketed in Northern Ireland), their use is not without issues. Whether vaccination of birds against highly pathogenic avian influenza virus (HPAIV) is allowed requires a change in UK policy.
Use of avian influenza vaccine may reduce poultry mortality and clinical signs of the disease following infection. However, vaccinated birds can still become infected, shed virus, and transmit the virus to other vaccinated or unvaccinated birds, mammals and humans.
As such, vaccination of birds may mask infection by increasing the time taken to detect and respond to detection of the virus. If appropriate surveillance is not put in place, this could result in a vaccinated flock being infected without detection as well as potentially creating a false sense of security, resulting in a possible relaxation of biosecurity and vigilance, further undermining the combined effectiveness of all measures to control the disease.
In addition, there are several practical and commercial disadvantages relating to the use of vaccines for high pathogenicity avian influenza which could present significant logistical and cost challenges to industry.
It will be necessary to be able to differentiate infected birds from vaccinated birds and to have accredited DIVA (differentiating infected from vaccinated animals) tests in place to ensure vaccination does not adversely affect surveillance and exports of poultry and their products to other countries.
The government continues to invest in avian influenza research and monitors the current situation with vaccine development and its usage internationally.
A joint industry, cross government ‘avian influenza vaccination taskforce’ has been established to make recommendations for the use of vaccination of poultry as a preventative measure against HPAI in the UK.
The avian influenza vaccination taskforce continues to review the reliability and validity of new vaccination data. This includes the definition of the epidemiological unit and how it affects the surveillance sampling and testing regime for vaccinated flocks. It also includes the costs, benefits, trade impacts and practicalities of different surveillance options.
The taskforce recognises these issues and supports the principles of vaccination to help mitigate the animal and public health impacts of HPAI. However, its advice will need to adapt to the dynamic nature of infectious diseases. This includes where we continue to see significant spread of the disease, despite control measures, like culling, biosecurity and housing order controls.
Adoption of vaccination will also require a thorough cost benefit analysis with respect to both the producer and government following the establishment of a proportionate surveillance strategy for vaccinated flocks.
The consideration of how game birds might be included in vaccination and surveillance schemes (considering their different production systems, movements, biosecurity, and risk factors) is also under discussion by the taskforce.
2. Development of HPAI vaccines
The currently authorised avian influenza vaccine in Great Britain (Nobilis Influenza H5N2) does not contain a contemporary H5 clade 2.3.4.4b antigen. As such, a lack of antigenic relatedness in H5 may impact upon level of protection.
However, several marketing authorisation applications for HPAI vaccines with efficacy claims against HPAIV of the contemporary H5 clade 2.3.4.4b subtype are currently being assessed by the Veterinary Medicines Directorate (VMD).
Additionally, there are several HPAI vaccines authorised elsewhere, including one recently in the EU, (Innovax-ND-H5 which is authorised throughout the EU and according to the Windsor Framework could be marketed in Northern Ireland) which have efficacy claims against the H5 subtype.
The avian influenza vaccination taskforce report will provide an analysis of the current knowledge of commercial H5 HPAI vaccines that have been evaluated in scientific studies, either laboratory or field based, including drawing on experiences from active H5 vaccination programmes.
There has been an acceleration of such studies in the last two years offering scientific insights to vaccine types and platforms that might be used in the future and how such vaccines would impact practical logistics, costs and surveillance requirements.
The selection of an appropriate vaccine is a critical step when considering vaccination and will depend on a number of criteria relevant to the local situation. Criteria includes, but is not limited to:
cost
applicability to multiple avian species
protection after one dose
optimal administration route, including options for mass vaccination with downstream practicalities (including in the hatchery at day-old or in-ovo)
duration of the protective immunological (antibody) response
capability to identify infected birds in a vaccinated population
impact of immunity to vectors where viral vectors are used to express AIV antigens
ability of vaccines to produce a protective response in the presence of maternal antibodies
antigenic relevance of the antigen present in the vaccine utilised
flexibility of the system to alter antigenic components relevant to the induction of protective antibodies
No current vaccine or vaccine technology meets all these criteria. Any HPAIvaccination programme must select the licensed vaccine that best meets these needs.
3. Process or authority for approval
The Veterinary Medicines Directorate (VMD) is the UK competent authority for the regulation of veterinary medicinal products (VMPs). It is responsible for the assessment of marketing authorisation applications submitted by the veterinary pharmaceutical industry to authorise and make available good quality, safe and efficacious VMPs, including veterinary vaccines.
A marketing authorisation is required to place a VMP on the relevant UK markets for sale and supply. A Great Britain marketing authorisation is required for Great Britain. A Northern Ireland, or an EU centralised marketing authorisation is required for Northern Ireland.
The respective marketing authorisations are based on the relevant requirements of the Great Britain Veterinary Medicines Regulation 2013 (‘VMR’), as amended and for Northern Ireland, Regulation (EU) 2019/6.
Additionally, in the event of a serious epizootic disease such as HPAI, the Secretary of State may permit in writing the administration of immunological veterinary medicinal products without a marketing authorisation, in the absence of a suitable medicinal product and may publicise any permit as the Secretary of State sees fit (VMR 2013, Schedule 4, paragraph 4).
4. Additional considerations
4.1 International trade
The World Organisation for Animal Health (WOAH) guidance states that vaccination for HPAI should not be a barrier to safe international trade in poultry commodities, if properly implemented.
Despite this, concerns about potential impacts on international trade continue to limit use of vaccination in many areas globally.
If HPAI vaccination is to be permitted, the UK will need to provide information and assurances to trading partners. For example, we would need to demonstrate we have an effective surveillance programme and enough capacity to provide an acceptable level of assurance that vaccination is not simply masking infection, which could spread through trade in poultry commodities.
It may still be difficult to negotiate continued market access, as countries may have different views on the acceptable level of risk.
Trading partners may want to carry out their own risk assessments and could apply safeguard measures (for example, introduction of bans, or extra testing and certification to ensure trade can continue).
It is likely that some trading partners would apply a precautionary approach and may introduce restrictions on some exports of poultry, poultry products or both, at least initially. We are aware of such restrictions having been applied to exports from other countries that have used vaccination.
Also, some current UK export health certificates contain clauses which will prevent their use if HPAI vaccination is permitted. These would require renegotiation with the competent authorities in the destination countries.
The government will work to avoid trade restrictions as far as possible in the event that preventative HPAI vaccination is to be permitted and will seek to reverse any restrictions that may be applied. This is likely to take time to achieve and may ultimately be unsuccessful in some cases.
This means the benefits of HPAI vaccination will need to be weighed against the likely loss of some export opportunities, at least in the short term. Any trade effects may not fall directly on the sectors who would most benefit from HPAIvaccination.
4.2 Northern Ireland and Great Britain movements
Any policy on HPAI vaccination will require careful consideration of the effects on the movement of poultry and poultry products between Northern Ireland and Great Britain.
Product regularly moves in both directions between Great Britain and Northern Ireland and may then be exported onwards to the EU or rest of the world. A decision to implement vaccination in poultry in Great Britain and not in Northern Ireland would have repercussions for the movement of such product.
4.3 Surveillance
The WOAH terrestrial code requires carrying out surveillance in vaccinated flocks to ensure the absence of virus circulation, with the testing being repeated at an appropriate frequency. It also requires evidence of the effectiveness of the vaccination programme, and this evidence is to be gathered during the surveillance activities.
For emergency HPAI vaccination, the objective of the surveillance will focus on the early detection of the HPAI, whilst for its use as a preventive measure the focus will be on attaining a high level of confidence in freedom from the disease.
Several surveillance options based on virological testing of dead birds at set intervals, in combination with active surveillance of live birds, are currently being considered for each of the HPAI vaccination strategies.
Currently, the EU has surveillance requirements to enable trade with countries that practice vaccination against an HPAI.
These include intensive testing regimes comprising virological testing of a sample of live birds every 2 weeks for a set period in the case of emergency vaccination, or the weekly testing of a representative sample of dead birds combined with the monthly testing of a sample of live birds in the case of preventive vaccination.
4.4 Costs and benefits
The avian influenza vaccination taskforce’s full report will include a comparison of preventative vaccination rollout costs at a national level and the cost of a HPAIoutbreak along with costs of necessary surveillance measures. This will indicate the potential value for money that using an HPAI vaccine in the UK will provide.
5. Next steps
The avian influenza vaccination taskforce will continue to survey the veterinary medicine pharmaceutical industry on their suitable HPAI vaccines, either existing or in development.
The information collected will be used to help formulate the taskforce’s recommendations for development of future vaccination strategies to control the outbreaks of HPAI in the UK.
The taskforce will publish a more detailed report in summer 2025.
The taskforce will also engage with relevant public health experts, to ensure the potential effect of any proposed widespread avian vaccination programme on human health is considered.
The taskforce’s report will be considered by the UK animal disease policy group, allowing for due consideration by the devolved governments.
The relevant GOV.UK guidance will also be updated.
6. Further information
Get more information on:
7. Organisations involved
This statement has been agreed by the following:
government’s exotic diseases policy leads for:
England
Scotland
Wales
Northern Ireland
Veterinary Medicines Directorate
Animal and Plant Health Agency (APHA)
British Poultry Council
British Egg Industry Council
British Free Range Egg Producers Association
British Veterinary Poultry Association
Game Farmers’ Association
Industry Veterinarians (Crowshall Veterinary Services, Slate Hall Veterinary Services)
National Farmers Union
National Farmers Union of Scotland
Science and Research (The Pirbright Institute)