French push for Avian Influenza vaccines

Ducks slaughtered due to the avian flu outbreak at a farm in Lohitzun-Oyhercq, southwestern France last month. Picture: Gaizka Iroz/AFP

The possibility of European farmers having to vaccinate their 400 million egg-laying hens and about 900 million broilers reared per year has emerged, as French agriculture minister Julien Denormandie pushes EU states to approve avian flu vaccination for poultry.

After the worst ever avian flu season in countries such as the UK, Germany, Belgium, the Netherlands and Italy, Denormandie wants vaccines approved for all 27 EU member states, as one of his objectives during France’s presidency of the EU, which runs until the end of June.

The French Government announced just last week that it would cull up top 1.3 million birds in the coming weeks to fight a surging outbreak of avian flu on poultry farms. All ducks, chickens and turkeys must be culled in some 226 municipalities in southwestern France.

However, Denormandie is unlikely to get his way. There are good reasons why vaccination of poultry against bird influenza is generally forbidden by the European Commission and by most governments in Europe.

They prefer to reply on early reporting of bird flu outbreaks, rapid action, biosecurity, culling and surveillance. Disadvantages with vaccines include some vaccinated birds still transmitting flu if they became infected, increasing the time taken to detect and eradicate the virus disease.

Influenza viruses can mutate rapidly, rendering a vaccine less useful. The vaccines would have to be individually injected into each bird, and it can take up to three weeks to deliver immunity. 

Some poultry would need two doses, while vaccine efficacy has not been proven for ducks, geese and game birds. Officials say vaccination may also induce a false sense of security, resulting in a relaxation of biosecurity and vigilance.

And it is difficult to differentiate infected from vaccinated birds, and many countries refuse to import products from vaccinated poultry. However, Denormandie has insisted there is “no other solution in the long term than to have vaccination.” 

“While we have invested enormously on biosecurity measures, tomorrow we need to be able to fight this virus with the help of the vaccine,” he said.

The French-based World Organisation for Animal Health says vaccination alone cannot control bird flu, if eradication is the desired result. Without monitoring, strict biosecurity, and the depopulation of infected flocks, the viruses could become endemic in vaccinated poultry populations. 

Vaccination could be used to protect susceptible poultry populations from infection. But any decision to use vaccination must include an exit strategy to enable the ending of vaccination, said the World Organisation.

The introduction of Highly Pathogenic Avian Influenza by migrating wild birds has become a perennial issue across Europe over the past 15 years in the autumn and winter, when they infect domestic wild birds, kept birds, and commercial poultry. The peak risk occurs between December and February.

There have been nearly 800 cases in the EU of this devastating disease since the autumn. The worst-hit were poultry keepers in Italy (307 cases), France (171), Hungary (112), and Poland (77). England had more than 70 outbreaks, Wales and Scotland about 10. Northern Ireland confirmed five outbreaks.

Ireland escaped relatively lightly, with five cases in flocks in Co. Monaghan and one in Co. Cavan. With no recent cases, bird flu surveillance zone controls were lifted north and south of the border on January 22.

The Department confirmed that across the six flocks are around 200,000 birds had been culled as a result of outbreaks in Ireland; however, "for GRPR reasons" claimed it was not possible to provide details of the number of birds culled in each flock.

The more than 85 cases in the UK compared with only 26 in the 2020-21 winter season, including cases confirmed over the last few days in Scotland and England. 

On January 6, the UK's Health Security Agency confirmed a case of bird-to-human transmission, but advised the risk to the public continued to be very low. The person acquired the infection from close, regular contact with infected birds kept in his home.

There is no evidence of onward human spread, and the infected individual was not significantly affected. Outbreaks can be very serious economically for individual poultry farmers and companies. 

Last July, researchers at The Pirbright Institute in England said they had have developed a vaccine that generates a faster and stronger immune response in poultry and reduces the amount of virus shed into the environment. They said this vaccine will also be less costly.