Bird flu vaccine: why countries have resisted it

STORY: French duck farmer Herve Dupouy has culled his flock four times since 2015 to stop the spread of bird flu.

As another deadly wave nears his farm, he said the once-taboo solution, vaccination, now provides the "one glimmer of hope".

Like Dupouy, many governments - including the EU - are reconsidering their opposition to bird flu vaccines for poultry.

Some poultry producers have resisted it so far over fears that vaccinations could mask the spread of disease,

meaning infected birds could slip through health checks undetected and infect others.

There are also fears that vaccinations would hurt exports to countries that have banned the practice.

The U.S., the world's biggest poultry exporter, is holding out against it for this very reason - despite being the hardest hit.

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

Culling poultry or locking them inside has not prevailed as a solution.

Since last year alone, over 200 million fowl have died worldwide – either because of the disease or mass culls, according to the World Organisation for Animal Health (WOAH).

And besides the cost of culling millions of ducks, chicken, turkeys and geese, there’s a growing fear that if the virus becomes endemic, the chances of it mutating and spreading to humans will only increase.

The world's largest poultry and egg producers told Reuters that this year has marked a global shift in the approach to vaccines due to the severity of the outbreaks.