The Bill and Melinda Gates Foundation on Sunday pledged that it would commit $1.2 billion toward wiping out all forms of polio globally as health experts from around the world gathered for a summit in Berlin.

"Polio eradication is within reach. But as far as we have come, the disease remains a threat," Bill Gates, co-chair of the foundation, said in a statement.

The sum will be donated to the Global Polio Eradication Initiative (GPEI), a public-private partnership led by national governments that aims to end the disease by 2026.

Polio is a highly contagious illness caused by a virus that enters the central nervous system and damages cells in the spinal cord and brain.

The disease can be fatal, and those who survive are often left paralyzed or with atrophied and twisted limbs.

Polio most often affects children under the age of five but can hit anyone who is not vaccinated. While there is no known cure, three injections of the vaccine provide nearly 100% immunity.

Since its launch in 1988, the GPEI has helped reduce polio cases by more than 99% worldwide and prevented more than 20 million cases of paralysis, the foundation said in a statement.

Pakistan and Afghanistan are the only two countries where the wild poliovirus remains endemic, though Malawi and Mozambique also detected imported wild polio cases in 2022.

"The last steps to eradication are by far the toughest. But our foundation remains dedicated to a polio-free future, and we're optimistic that we will see it soon," said Mark Suzman, CEO of the Bill & Melinda Gates Foundation, which is run by Microsoft Corp co-founder Bill Gates and his ex-wife Melinda French Gates.

Last month, the Pan-American Health Organization (PAHO) said Brazil, the Dominican Republic, Haiti and Peru are at very high risk for the reintroduction of polio. New York state is accelerating efforts to vaccinate residents after the virus was detected in wastewater samples. Cases were also detected in London and Jerusalem.

In March, a senior World Health Organization official said that the world is at a "dangerous moment" in the fight against diseases like polio, after an outbreak in Malawi.

The announcement came ahead of a key pledging moment that will be co-hosted by Germany and the GPEI on Oct. 18. The Gates Foundation is part of the GPEI, a major project between governments and international organizations. The foundation has contributed nearly $5 billion to GPEI.