Our team are hearing some questions from clients regarding the introduction of an avian influenza vaccine, and whilst it might seem like an obvious route for the poultry and game bird industry to take, there are a number of areas to consider.
Some European countries are further along in discussions, and Dutch scientists have already begun trials on chicken vaccines. In France, a trial is about to commence on the immunisation of ducks. Here in the UK, Defra’s current position is that emergency vaccination is not recommended as a means of controlling an outbreak and ‘stamping out’ is the most effective means of controlling an outbreak. Defra sees that early reporting, rapid action, biosecurity, culling and surveillance remain the most effective ways of protecting against and controlling avian influenza.
Here are some summary points covering the disadvantages of an avian influenza vaccine, as explained in November’s BFREPA publication. BFREPA is the British Free Range Egg Producers Association and plays a key role in UK egg industry, influencing legislation and shaping policy.
- Although the vaccines can reduce mortality, it is likely that some vaccinated birds would still be capable of transmitting avian influenza if they became infected, therefore increasing the time taken to detect and eradicate this virus
- Influenza viruses can mutate rapidly, which could render a vaccine less useful
- The vaccines present serious practical limitations in that they need to be delivered by individually injecting each bird. It can take up to 3 weeks for the birds to deliver optimum immunity, and some poultry require 2 doses, with a 4-6 week interval between these
- There is no proven efficacy of the vaccines in species such as ducks, geese and game birds
- It is difficult to differentiate infected birds from vaccinated birds
- There are welfare implications for birds through increased handling, especially when speed is necessary
- Vaccination may induce a false sense of security, resulting in a relaxation of biosecurity and vigilance
Ultimately, vaccination is not a straightforward solution. St David’s vets are working closely with other colleagues in the poultry veterinary industry and governing bodies to share information and create guidance that offers the best and most practical route to take to tackle the outbreak.
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