WHO Emergency Committee Highlights Rising Poliovirus Concerns Amid Increased Cases and Geographic Spread in 2024 Meeting

Published on Wednesday December 18, 2024

The fortieth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) regarding the international spread of poliovirus was convened on November 6, 2024, by the WHO Director-General. This virtual meeting, supported by the WHO Secretariat, brought together Committee members, advisers, and representatives from affected countries. They assessed the ongoing situation of wild poliovirus (WPV1) and circulating vaccine-derived polioviruses (cVDPV), considering the global targets for eradication set for 2027 and 2029 respectively.

Significant findings emerged from the technical updates presented for multiple countries including Afghanistan, Pakistan, and others. In 2024, 51 new WPV1 cases were documented—17 in Afghanistan and 34 in Pakistan—resulting in a total of 62 cases this year. This marked a spectacular rise in paralytic cases with Afghanistan experiencing a 283% increase, and Pakistan seeing a 550% increase compared to 2023. Environmental samples in Pakistan and Afghanistan also revealed an alarming rise in WPV1 samples, indicating an upward trend in both countries.

The meeting highlighted the geographic spread and reestablishment of WPV1 in historic reservoirs, such as Karachi and Peshawar in Pakistan, with most intense transmission observed in the Quetta Block and South Region of Afghanistan. Despite efforts involving synchronized campaigns, challenges persist. In Afghanistan, the shift to site-to-site campaign modalities and operational challenges in Pakistan's South KP, alongside increased attacks on health workers, have complicated eradication efforts. This situation is further compounded by the movement of undocumented migrants between Pakistan and Afghanistan, increasing the risk of cross-border poliovirus spread.

Furthermore, the Committee discussed the accidental WPV3 exposure in France, emphasizing the need for rigorous poliovirus containment measures. Regarding cVDPV, 2024 saw a reported 190 cases with significant activity in Nigeria, which alone accounted for 46% of global cVDPV2 cases this year. The transmission of cVDPV2 in the Horn of Africa and challenges faced in areas like northern Yemen, northern Nigeria, and eastern DR Congo were particularly concerning.

In conclusion, the Committee reaffirmed the global risk of poliovirus spread as a Public Health Emergency of International Concern (PHEIC), extending Temporary Recommendations for another three months. Countries impacted by WPV1 and cVDPV2 are urged to reinforce vaccination campaigns, heighten immunization coverage, and enhance surveillance measures to mitigate the risks of international transmission. Implementing immediate, intensified cross-border coordination and vaccination strategies remains vital to enduring global polio eradication efforts.

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