Key result
cVDPV2 accounts for ~86% of global cVDPV cases while WPV1 intensifies in Pakistan and Afghanistan.
Why the study?
Vaccine-associated paralytic poliomyelitis and vaccine-derived poliovirus threaten global polio eradication, making understanding the shifting epidemiology of WPV and VDPV critical for guiding elimination strategies.
Observational
Yes
The global eradication of polio faces dual challenges from the widespread dominance of cVDPV2 and the resurgence of WPV1 in endemic regions.
Sustained cVDPV2 dominance and WPV1 resurgence highlight vaccination gaps; leaves open optimal eradication strategies for prospective evaluation.
OBJECTIVES: Poliovirus primarily causes central nervous system diseases in children. Currently, among the three wild polioviruses (WPVs), only WPV1 remains, distributed in Pakistan and Afghanistan. However, vaccine-associated paralytic poliomyelitis and vaccine-derived poliovirus (VDPV) pose a threat to the global polio eradication goal. Understanding the shifting epidemiology of both WPV and VDPV is critical for guiding final elimination strategies. METHODS: We retrieved data from the Global Polio Eradication Initiative (GPEI) and analyzed WPV1 cases from 2017 to January 28, 2026, along with circulating VDPV (cVDPV) cases from 2021 to January 28, 2026. RESULTS: cVDPV2 was the dominant subtype, accounting for 4,819 of 5,585 cases (86.3%) across 57 countries, confirming its significant challenge to eradication efforts. WPV1 transmission intensified, with cases rising to 871 in 2024 and 769 in 2025, primarily in Pakistan (n=3,005) and Afghanistan (n=683). cVDPV1 and cVDPV3 exhibited limited geographical circulation. CONCLUSIONS: The prevalence and wide distribution of cVDPV2, along with the resurgence of WPV1 in its remaining strongholds, highlight the dual challenges facing the GPEI. These findings underscore the urgent need to maintain high vaccination coverage, improve environmental surveillance, and develop subtype-specific intervention strategies for sustained eradication.
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Sun et al. (2026) conducted an observational in Poliovirus. Wild poliovirus 1 (WPV1) and circulating vaccine-derived poliovirus (cVDPV) was evaluated on Prevalence and geographical distribution of poliovirus cases. Between 2017 and 2026, cVDPV2 was the dominant subtype globally, accounting for 86.3% of cVDPV cases across 57 countries, while WPV1 transmission intensified primarily in Pakistan and Afghanistan.
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