In a landmark announcement on Tuesday, the World Health Organisation (WHO) declared that Africa was free of the virus that causes polio. No polio cases were reported in the country this year or last year or the year before. It was in 2016 that the last case of polio was reported in Nigeria—the final country on the 54-nation African continent where the disease was endemic.

“Today is a historic day for Africa,” said Professor Rose Gana Fomban Leke, whose commission certified that no polio cases had occurred on the continent for the past four years. WHO said that 1.8 million children were saved from the virus because of the eradication efforts.

In 1996, Africa had 70,000 polio cases. As of now, only two countries in the world have active polio cases-Pakistan and Afghanistan.

“This is a momentous milestone for Africa. Now future generations of African children can live free of wild polio,” said Matshidiso Moeti, the WHO’s regional director for Africa. He also thanked governments, communities, global polio eradication partners and philanthropists.

The declaration was made at a ministerial-level virtual conference on health issues in Africa. Meanwhile, the Democratic Republic of Congo declared that a 25-month epidemic of measles that killed more than 7,000 children was now over.

Poliomyelitis — the medical term for polio — is an acutely infectious and contagious virus that attacks the spinal cord and causes irreversible paralysis in children. Though a virus was discovered in the 1950s most of the poorer countries in Asia and Africa did not have access to it.