The Epinhood (TEH)

• Virus Detection: Circulating vaccine-derived poliovirus type 2 (cVDPV2) detected in wastewater samples in Finland, Germany, Poland, Spain, and the United Kingdom in 2024.
• Public Health Significance: Detection of cVDPV2 serves as a wake-up call for continued vigilance and vaccination efforts to achieve global polio eradication.
• Global Context: The Global Polio Eradication Initiative (GPEI), established in 1988, has made significant progress towards a poliovirus-free world.
• International Spread Risk: Risk persists due to vaccine-derived poliovirus outbreaks and wild-type 1 poliovirus circulation in Afghanistan and Pakistan.
• Circulating VDPV2 Detection: cVDPV2 detected in wastewater samples in Finland, Germany, Poland, Spain, and the UK since September 2024.
• Environmental Surveillance: Routine or research-based surveillance in five European countries supports early detection of poliovirus reintroduction or circulation.
• Poliovirus Surveillance Laboratories: Specialized laboratories in Finland, Germany, and the UK conduct poliovirus surveillance using WHO-recommended workflows.
• Detection Reporting and Response: All countries reported poliovirus detections through IHR and EWRS, enabling timely risk assessment and collaboration with WHO, CDC, and ECDC.
• Wastewater Sample Handling: Wastewater samples were processed in separate laboratory areas with appropriate biocontainment measures to prevent cross-contamination with clinical samples.
• Cell Lines for Virus Detection: Two cell lines, L20B (transgenic mouse) and RD-A (human), were used for detecting poliovirus and non-polio enteroviruses in wastewater.
• Virus Isolation and Characterization: Virus isolation on L20B cells, followed by intratypic differentiation (ITD) or VP1 amplification and sequencing, was used to characterize the virus.
• Enterovirus Detection Methods: Direct detection of enteroviruses from concentrated wastewater samples was achieved through VP1 amplification and sequencing using Oxford nanopore technology (ONT). • Software Used: Geneious Prime 2020.0.3, Sequencher 5.4.6, MEGA X, Microreact.
• Phylogenetic Analysis: Maximum likelihood method and Tamura-Nei model were used to infer the phylogenetic relationships between cVDPV2 isolates.
• Genome Analysis: Whole genome sequences were aligned to the Sabin 2 vaccine reference sequence to identify recombination events.
• VDPV2 Detection Locations: Circulating VDPV2 strains detected in Finland, Spain, Poland, Germany, and the UK.
• VDPV2 Detection Frequency: Higher detection frequency in Germany compared to other countries, suggesting potential differences in infection levels or detection sensitivity.
• Genetic Relationship of VDPV2 Strains: All European cVDPV2 strains genetically related to each other and linked to the NIE-ZAS-1 lineage originating in Nigeria, indicating undetected circulation for at least a year.
• Virus Origin: Genetic diversity suggests simultaneous importations of genetically related viruses into different European locations from an unknown country or area.
• Genetic Structure: European cVDPV2 NIE-ZAS-1 strains exhibit a double recombinant structure, having replaced sequences upstream and downstream of the capsid coding region with those from unidentified enterovirus C strains.
• Potential for Paralysis: Recombination with enterovirus C strains is expected to have removed the attenuation properties of Sabin 2, increasing the potential for paralytic disease.
• Wastewater Surveillance Importance: Detects silent poliovirus circulation, particularly in polio-free countries using inactivated polio vaccine.
• cVDPV2 Detection: Genetically related cVDPV2 strains detected in wastewater samples from five European countries.
• Public Health Response: Early detection through wastewater testing allows for timely public health measures, including risk assessments and targeted vaccination campaigns.
• Vaccine-Associated Paralytic Poliomyelitis (VAPP): A rare but serious complication of the oral poliovirus vaccine (OPV) where the live-attenuated virus mutates and causes paralysis.
• Risk Factors for VAPP: Individuals with immunodeficiency disorders, those receiving their first dose of OPV, and those who received intramuscular injections before OPV.
• VAPP Transmission: Occurs in recently vaccinated individuals (recipient VAPP) and in susceptible individuals exposed to the vaccine virus (contact VAPP).
• VAPP Risk by Serotype: Type 3 is most associated with VAPP, type 2 with immunodeficient individuals and contact cases, and type 1 with fewer cases.
• Global VAPP Burden: Estimated at 250-500 cases annually based on a risk of 1 case per 2-4 million births.
• Impact of IPV and OPV Withdrawal: IPV introduction and OPV type 2 withdrawal are expected to reduce VAPP risk, with studies showing elimination in countries adopting similar strategies.
• Poliomyelitis Vaccine Safety: Cases of paresis occurred from inadequately inactivated poliovirus vaccine in the 1950s.
• Poliomyelitis Outbreak Information: Recent polio outbreaks and updates are available on the ProMED website.
• Poliomyelitis Research: References to research papers on polio vaccine safety and outbreaks are provided.
• Disclaimer: ProMED makes every effort to verify the reports, but the accuracy and completeness of the information are not guaranteed.
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