French duck farmer Herve Dupouy has culled his flock four times since 2015 to stop the spread of avian influenza but as a wave of deadly outbreaks nears his farm once again, he says it's time to accept a solution once considered taboo: vaccination, according to a report from Reuters.

"The goal is that our animals don't fall ill and that they don't spread the virus," Dupouy said on his farm in Castelneu-Tursan in southwestern France. "Our job as farmers is not to gather dead animals."

Like Dupouy, more and more governments around the world are reconsidering their opposition to vaccines as culling birds or locking them inside has failed to prevent bird flu returning to decimate commercial flocks year after year.

Reuters spoke to senior officials in the world's largest poultry and egg producers, along with vaccine makers and poultry companies. They all said there had been a marked shift in the approach to vaccines globally due to the severity of this year's avian influenza outbreak, though the biggest exporter of poultry meat, the United States, told Reuters it remains reluctant.

Besides the cost of culling millions of chickens, ducks, turkeys and geese there is also a growing fear among scientists and governments that if the virus becomes endemic, the chances of it mutating and spreading to humans will only increase.

"That's why every country in the world is worried about bird flu," French agriculture minister Marc Fesneau said.

"There's no reason to panic but we must learn from history on these subjects. This is why we are looking into vaccinations at the global level," he told Reuters.

Most of the world's biggest poultry producers have resisted vaccinations due to concerns they could mask the spread of avian influenza and hit exports to countries that have banned vaccinated poultry on fears infected birds could slip through the net.

But since early last year, avian influenza has ravaged farms around the world, leading to the deaths of more than 200 million birds because of the disease or mass culls, the World Organisation for Animal Health (WOAH) told Reuters.

The mass culls last year also sent the price of eggs sky-rocketing, contributing to the global food crisis.

US holds out 

Mexico started emergency vaccinations last year while Ecuador said this month it planned to inoculate more than two million birds after the virus infected a 9-year-old girl.

France is on track to start vaccinating poultry in September, agriculture minister Fesneau told Reuters, before the return of migrating wild birds that can infect farms.

The EU, meanwhile, agreed last year to implement a vaccine strategy across its 27 member states.

Brussels has also normalised its poultry vaccination rules, which are due to come into force next month. They will ensure poultry products and day-old chicks can be traded freely within the bloc, a European Commission spokesperson told Reuters.

China, which consumes most of its poultry production domestically, has been vaccinating against avian influenza for nearly 20 years and has managed to sharply reduce outbreaks.

But the biggest producer of poultry meat in the world, the United States, is holding out for now.

The United States has been hit hardest worldwide in the latest outbreak with a toll of more than 58 million birds in the past year, followed by Canada, while France has suffered the most within the EU, WOAH data showed.

But the fear of trade restrictions remains centre stage for countries reluctant to vaccinate poultry against avian influenza.

While vaccines can reduce death rates, some vaccinated birds could still contract the disease and transmit it, effectively masking the spread of the virus.

That's why some big buyers of poultry meat and live birds have banned imports from countries where vaccines are permitted, for fear of bringing in the virus as well.

Avian influenza can also mutate rapidly and reduce the efficacy of vaccines while programmes are costly and time consuming, as shots often need to be administered individually. And even once birds have been vaccinated, flocks need to be monitored.

"The use of a vaccine at this time would have detrimental impacts on poultry trade while still necessitating response activities such as quarantine, depopulation, and surveillance testing," the US Department of Agriculture (USDA) told Reuters.

Given trade restrictions on vaccinated poultry, bilateral negotiations would be needed to clear exports to those markets and avoid unfair competition, Philippe Gelin, chief executive of France's LDC, one of Europe's largest poultry firms.

French minister Fesneau told Reuters that Paris was negotiating with its non-EU trade partners to allow exports of vaccinated poultry while there were also bilateral talks at the EU level with countries outside the bloc.

MRNA poultry vaccines

Brazil, the world's largest poultry exporter, has so far avoided an outbreak - and the need for vaccines - though the virus is getting closer with several of its neighbours including Bolivia reporting outbreaks.

But countries such as France, which spent 1.1 billion euros ($1.2 billion) last year compensating poultry farmers for their losses, believe it's time to bite the vaccination bullet.

"This is a huge economic loss," said Gilles Salvat, deputy director of the research division at French health security agency ANSES. "We won't avoid occasional introductions (of the virus) via wildlife or via a contaminated environment, but what we want to avoid is these occasional introductions spreading throughout the country."

As part of the EU-wide strategy, France is carrying out tests on vaccines for ducks, which are very receptive to the virus and remain asymptomatic for many days, increasing the risk of transmission to other farms.

The Netherlands is testing vaccines on egg-laying hens, Italy is doing the same on turkeys and Hungary on Pekin ducks, with the results from the EU trials expected in the coming months.

France's Ceva Animal Health, one of the main companies developing avian influenza vaccines along with Germany's Boehringher Ingelheim, said initial results were "very promising," notably by sharply reducing the excretion of the virus by infected birds.

Ceva said it was using the mRNA technology used in some COVID shots for the first time in poultry vaccines.

The global market for avian influenza vaccines would be about 800 million to 1 billion doses per year, excluding China, said Sylvain Comte, corporate marketing director for poultry at Ceva.

Although the risk to humans from avian influenza remains low, and there have never been cases of human-to-human transmission, countries must prepare for any change in the status quo, the World Health Organization said last week.

The recent COVID crisis has shown the risk of a virus found in animals mutating or combining with another influenza virus to make the jump to humans - and lead to a global pandemic.

The H5N1 strain prevalent in the latest bird flu outbreak has killed several mammals, including minks in Spain, foxes and otters in Britain, a cat in France and grizzly bears in the United States.

"Without being alarmist, we should be careful and not let this virus circulate too intensively and for too long," said Salvat at French agency ANSES.

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