Cases of polio have declined by 99% since the 1990s thanks chiefly to mass vaccination campaigns worldwide.

However, eradicating the disease completely has proven more challenging. The wild form of polio is now only endemic in Afghanistan and Pakistan, but the vaccine-derived strain is more widespread.

Vaccine-derived polio can occur when children are immunized with a vaccine containing a weakened version of the live virus. They are protected, but the weakened virus excreted by these immunized children can spread and mutate among an unvaccinated population, ultimately becoming harmful.

Both forms of the disease are often asymptomatic, but in rare cases can paralyse and kill children.

“Humanity has only eradicated a single disease: small pox. And that was over 50 years ago. Today, we are on the verge of ending another: wild polio virus. The virus that once paralysed 7,000 children every week, has only paralysed 9 people this year,” Bill Gates told reporters at a press conference.

“But while Polio is nearly gone, there are also another 280 children who have been struck by a different polio variant.”

The financing package is expected to reach 1.1 billion euro ($1.17 billion), as part of Europe’s Global Gateway investment strategy. UNICEF and the World Health Organisation will be the implementing partners.

By Julia Payne and Jennifer Rigby

(Reporting by Julia Payne and Jennifer Rigby; Editing by Andrew Heavens and Sharon Singleton)