The British Veterinary Association
Statement on the Use of Vaccination as a Control Option for Avian Influenzahttp://www.bva.co.uk/policy/issues/AI_vaccination_statement.pdf
Or see below for full text. Extract:
The BVA supports the use of vaccination under the following circumstances:
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- Vaccinating high risk birds, from zoos or private bird collections, which cannot be moved indoors for welfare reasons.
- Where there is a high risk of spread of the highly pathogenic avian influenza virus to the UK.
- Preventative vaccination in high risk areas where it is felt impossible to maintain adequate separation of domestic flocks from a high density of wild birds suspected of carrying AI, (based on a risk assessment).
- Emergency vaccination as a disease control option where other control methods have failed to contain the further spread of infection, or for high risk groups in the near vicinity as detailed above if preventative vaccination has not already been considered
- If the level of culling as a control method reaches such a level as to be unjustifiable on ethical or welfare grounds, as has now been declared in the Asian context by the WHO, OIE and FAO.
- If the disease becomes endemic in the UK and persists at high levels in the wild bird population.
- Where the welfare of birds is considered to be severely compromised; for example, free range flocks that are required to be housed indoors for long periods. Vaccination would allow the birds to be returned outdoors and they should be constantly monitored (use of sentinel birds).
Wild bird surveillance should be stepped up immediately across the EU to ensure rapid detection of the virus and to assess the real level of infection across Europe Vaccination should be considered as part of the future control of the disease when it is identified in the UK in wild birds or domestic poultry
- Defra’s contingency vaccination policy should be finalised immediately
- The vaccination plans should be submitted to the EU Commission before seeking approval to actually start vaccinating
- A vaccine order should be placed in line with the UK’s contingency plan
- The contingency vaccination plans should be re-examined daily/weekly
Statement on the Use of Vaccination as a Control Option for Avian
The BVA supports the possible use of vaccination as part of a national control plan for avian
influenza, but would like to stress that there are many issues that need to be taken into
account when considering the use of vaccines for disease control. The BVA does not support
the use of vaccination in domestic poultry before avian influenza is identified in the UK.
At present (24/02/06):
No cases of highly pathogenic avian influenza have been detected in wild birds within the UK.
To date only one case of H5N1 has been confirmed in ducks and chickens in an animal
sanctuary in Austria (the first EU case in poultry). One suspected case of highly pathogenic
avian influenza is also under investigation in domestic poultry premises in the EU (France).
Migratory waterfowl, believed to be associated with the spread of H5N1 are now travelling
eastwards, away from the UK
The BVA believes that under the current conditions, it is not yet appropriate to carry out
preventative vaccination of the UK’s domestic poultry flocks as it may severely compromise
the ability to recognise and react quickly to any introduction of the virus to our domestic
The observed, limited transmission between wild birds and poultry within the EU countries to
date is encouraging and the UK may be able to control this disease by limiting contact
between wild birds and domestic poultry and through early detection and ‘stamping out’
(culling of infected or close contact birds).
It should be recognised however that these control measures may not remain the
most appropriate option if either:
othe level and duration of infection in the wild bird population increases
othe risk of transmission to domestic poultry increases significantly.
Thus constant surveillance of the disease is necessary and vaccination should always be
considered as a control option for the future. The UK must be prepared to react immediately
to any change in risk that will necessitate the use of a vaccine, and we must ensure that the
UK has the necessary measures in place in order to allow us to respond effectively.
The BVA recognises that considerable surveillance has taken place in the UK since October
2005 but we strongly urge Defra to continue to step up surveillance in wild birds. This will
ensure that highly pathogenic avian influenza is detected at the earliest opportunity to ensure
that isolation and eradication is immediate. We must also ensure that efforts are made to
determine the level of infection in wild birds across Europe as this will have an impact on the
level of risk posed to the UK.
Defra should now, with urgency, be submitting all necessary vaccination plans to the
European Commission so that, when it becomes necessary, EU approval for the use of
vaccination can be sought and acquired quickly.
The statement below outlines the pros and cons of vaccination from a veterinary perspective
and outlines the types of vaccination that are felt to be appropriate and under which
circumstances. It also reinforces the need to continually monitor the spread of this continually
•We do not support vaccination of domestic poultry before avian influenza is identified in
•Early detection, isolation and eradication is the best approach to controlling the spread
of this disease
•Poultry owners should be making efforts to protect their flocks by preventing contact
between poultry and wild birds and their droppings by:
oIncreasing biosecurity measures
oKeeping domestic birds away from lakes and waterways
oFeeding and watering domestic poultry indoors
oPreparing to house free-range birds within 24 hours should Government
•Wild bird surveillance should be stepped up immediately across the EU to ensure rapid
detection of the virus and to assess the real level of infection across Europe
•Vaccination should be considered as part of the future control of the disease when it is
identified in the UK in wild birds or domestic poultry therefore:
oDefra’s contingency vaccination policy should be finalised immediately
oThe vaccination plans should be submitted to the EU Commission before
seeking approval to actually start vaccinating
oA vaccine order should be placed in line with the UK’s contingency plan
oThe contingency vaccination plans should be re-examined daily/weekly
•Vaccination can be an important additional measure but it does not prevent infection so
vaccinated birds must be subject to continued monitoring for the virus. Biosecurity
measures must be maintained in vaccinated birds.
•We support the vaccination of high risk birds, from zoos or private bird collections,
which cannot be moved indoors for welfare reasons.
Supporting comments: The use of vaccination to control the spread of avian
Vaccination is not a solution in itself and should be used in conjunction with other control
measures, which include heightened biosecurity, movement controls and culling or ‘stamping
out’ in control zones (3 km and 10 km) around any disease outbreak.
Biosecurity measures are essential to control an outbreak as avian influenza will still be able
to spread with or without vaccination. The use of a vaccine would also have to be
accompanied by increased surveillance and monitoring of the vaccinated birds, in order to
pick up any superimposed infection within a flock.
It is necessary to be able to differentiate vaccinated and infected birds from those that are
merely vaccinated. Current vaccines allow for such a ‘DIVA’ (differentiating infected from
vaccinated individuals) strategy to be followed. However, their effectiveness, and the
possibility of following a ‘DIVA’ strategy will depend on the type of vaccine and the current
strain of the avian influenza virus circulating. Sentinel (unvaccinated) birds should also be
used to test for any infection in a vaccinated flock.
Vaccination can be used in two ways as part of a control strategy:
•As a preventative measure prior to the detection of the virus
•Or as an emergency control measure for use once the virus has been detected.
The UK Government has outlined plans for both applications in their draft vaccination plan,
which is part of the UK’s transposition of the AI Directive into UK law. The BVA is fully
supportive of keeping every available disease control option open for the future and endorse
the consideration of both applications for disease control.
There are limitations with the current vaccines available. They are inactivated and need to
be injected into each individual bird, and vaccination will probably have to be administered on
two occasions. This makes vaccination a very expensive exercise in terms of manpower and
time. It normally takes from 2-5 weeks for the birds to build up the necessary level of
immunity. Vaccination can also have an effect on the welfare of layers; handling depresses
egg production and can result in peritonitis (an inflammation of the peritoneum, the
membrane that lines the wall of the abdomen and covers the abdominal organs) which can
The current vaccines also do not protect birds from becoming infected with AI, nor do they
prevent such vaccinated birds from excreting the virulent virus. However, trials indicate that
the quantity and duration of such excretion are considerably reduced. Confirmation of the
presence of virus (with or without overt signs of disease) will trigger the slaughter of infected
flocks and the establishment of a 3km protection zone and 10 km surveillance zone. It must
also be stressed that vaccination against one strain of the virus will not protect the UK flocks
from the introduction of another strain of the virus, which for a rapidly mutating virus is a
significant factor to consider.
The advantages of vaccination
The advantages of vaccination in terms of disease control are that it significantly reduces the
clinical severity of the disease and the transmission of the virus between birds. Therefore
vaccination has the ability to reduce the spread of infection in birds, and to reduce the risk to
those working with poultry. It would also provide some protection for free range flocks that
cannot be held indoors for a protracted period.
Vaccination in other EU Member States:
From the latest information available, France and the Netherlands have recently been given
permission to begin vaccination programmes.
Defra update 23/02/06 on the SCoFCAH meeting on vaccination (21 - 22 February)
At the meeting the Netherlands and France submitted detailed plans which were agreed.
This is a summary of them.
The Netherlands proposed to immediately vaccinate all backyard flocks and free range laying
hens over seven weeks old (up to 8 million birds). This was due to their view of the high level
of risk across their territory with a very concentrated poultry population, extensive aquatic
area and being a cross roads for several main migratory routes for wild birds and the
impracticality of housing;
France proposed to vaccinate from March just geese and ducks over 3-4 weeks old (around
900,000 birds) in three Departments on the Atlantic coast (that is not including the area
where there has been an outbreak) which they assessed as high risk for similar reasons
around migratory routes, high density and aquatic areas.
France and Denmark also circulated plans to vaccinate zoo birds (following plans already
submitted by the Netherlands, Belgium and Portugal) and Sweden also announced its
intention to do so.
BVA supports the use of vaccination under the following circumstances:
•Vaccinating high risk birds, from zoos or private bird collections, which
cannot be moved indoors for welfare reasons.
•Where there is a high risk of spread of the highly pathogenic avian influenza virus
to the UK.
•Preventative vaccination in high risk areas where it is felt impossible to
maintain adequate separation of domestic flocks from a high density of wild birds
suspected of carrying AI, (based on a risk assessment).
•Emergency vaccination as a disease control option where other control
methods have failed to contain the further spread of infection, or forhigh risk
groupsin the near vicinity as detailed above if preventative vaccination has not
already been considered
•If the level of culling as a control method reaches such a level as to be
unjustifiable on ethical or welfare grounds, as has now been declared in the
Asian context by the WHO, OIE and FAO.
•If the disease becomes endemic in the UK and persists at high levels in the wild
•Where the welfare of birds is considered to be severely compromised; for
example, free range flocks that are required to be housed indoors for long periods.
Vaccination would allow the birds to be returned outdoors and they should be
constantly monitored (use of sentinel birds).
Vaccination of zoo birds:
The collective term ‘zoo birds’ is used to include rare and endangered species housed in
zoological and private collections. The justification for the vaccination of zoo birds and private
collections is a separate issue to the vaccination of domestic flocks and BVA, BVZS (British
Veterinary Zoological Association) and BIAZA (The British and Irish Association of Zoos and
Aquariums) believe that in order to preserve biodiversity such collections should be
vaccinated. Many species cannot be held indoors or adequately separated from wild birds
without severe consequences to their welfare.
Any use of vaccine in this scenario would not be to control a disease outbreak but as a
conservation measure for rare and endangered species. Contingency planning of this sort is
consistent with both UK and EU policy. Given that current information indicates that some
larger zoo birds may require a second vaccination three weeks after the first and that the
maximum protective effect may take up to 5 weeks, this means it could take up to 8 weeks to
protect a zoo bird using vaccination. Consequently, the BVA, BVZS and BIAZA believe that
Defra should now be seeking EU agreement to our vaccinating high risk birds from zoos and
Decision-making on the birds to vaccinate and methods of monitoring should be made on a
case by case basis taking into account welfare and physical practicalities as well as previous
data available about the use of such vaccines in zoo birds; consultations between zoo
veterinary professionals and Defra should inform decision-making in this area. Vaccination of
individual zoo birds should take into account the following areas:
- The concept of epidemiological units
- Bird eligibility
- Vaccine logistics
- Implementation of vaccination
- Surveillance and testing – along with the use of a ‘DIVA’ strategy
Vaccination of non-domesticated species is not without risk to the birds as they are not used
to being handled and to be done safely it will take time. The birds will have to be caught at
least twice for the first and second injection which is considered to be a very stressful
experience for many species.
Vaccination has produced lethal effects in some zoo birds and we do not know how many of
the species will react to the vaccine. Therefore veterinary zoological experts should be
consulted on the use of vaccine for the different species kept.