Two Countries Defeat Wild Poliovirus Transmission

Amongst the 34 countries reporting polio cases in 2024, two African countries confirmed today the closure of the wild poliovirus type 1 (WPV1) outbreak, marking a significant milestone in the fight against polio in the African region.

On May 14, 2024, following thorough assessments in Malawi and Mozambique, an independent Polio Outbreak Response Assessment Team recommended the closure of these WPV1 outbreaks.

The last WPV1 case in the African Region, linked to a strain circulating in Pakistan, was reported in Mozambique's Tete Province in August 2022. A total of nine cases were detected in Mozambique and neighboring Malawi, where the outbreak was declared in February 2022.

In a coordinated response, more than 50 million children in five southern African countries have been vaccinated against the virus.

These countries have administered over 100 million vaccine doses in the most at-risk areas. The strategy to prevent this outbreak from getting out of hand relied on synchronizing and coordinating vaccination plans across five countries and monitoring vaccination activities.

These tactics proved vital in identifying and reaching all eligible children in cross-border areas to avoid the risk of paralysis due to the virus.

"Closing polio outbreaks is possible when national governments, local health workers, community mobilizers, and global partners come together to prioritize a rapid and timely response to protect children from this devastating disease," said Dr. Chris Elias, president of Global Development at the Bill & Melinda Gates Foundation, in a press release.

"Malawi, Mozambique, and the entire Southern-African region are setting the example for what it takes to urgently improve vaccination campaigns and disease surveillance systems."

"Commitments like these will help us achieve a world free of all forms of poliovirus."

Since 1988, the incidence of wild poliovirus has been reduced by more than 99%, from more than 350,000 annual cases in more than 125 endemic countries to four cases in 2024 from two endemic countries (Pakistan and Afghanistan).

In 2023, only 12 cases of WPV1 were detected globally.

However, the U.S. CDC says that some international destinations have a circulating poliovirus. Before traveling to at-risk areas, ensure you are up to date on your polio vaccines.

In 2024, most African polio vaccination campaigns deploy the WHO-approved nOPV2 vaccine.

Since launching in 2021, approximately 1 billion nOPV2 doses have been administered in more than 35 countries.

nOPV2 is a novel oral poliomyelitis vaccine type 2 developed to address the evolving risk of circulating vaccine-derived polio. It has been 'triple-locked' using genetic engineering to prevent it from becoming harmful and producing a gut reaction.

As a result, nOPV2 is reported to be more genetically stable than currently approved oral polio vaccines.