LONDON, Nov. 27 -- The government of the United Kingdom issued the following news:
Amajor new studyin Nature Microbiologyled by Imperial College Londonandsupported by the Medicines and Healthcare products Regulatory Agency (MHRA) has uncovered critical insights into the spread patterns of vaccine-derived poliovirus type 2 (cVDPV2), offering valuable intelligence to support global efforts to eradicate polio.
The research, conducted by an international team including scientists from the MHRA's Vaccines, Science and Research Group, analysed 3,893 cVDPV2 cases across 74 outbreaks in 39 countries between May 2016 and September 2023.
Keyfindings
The study reveals that vaccine-derived poliovirus spreads at a consistent median velocity of 2.3 kilometres per day,predominantly betweenneighbouring countries. Thisrepresentsthe first comprehensive assessment of the spatiotemporal dynamics of cVDPV2 transmission since the global withdrawal of type 2 oral poliovirus vaccine in 2016.
Analysis shows that whilst most outbreaksremainrelativelycontained-with a median of just 4.5 cases-some have spread extensively, affecting up to 14 countries. International borders were found to significantly slow transmission,likely due tohigher immunity levels created by vaccination campaigns, potentially decreasing spread velocity by up to 38%.
The research alsodemonstratesthat historic wild-type poliovirus spread patterns closely resemble current cVDPV2 transmission routes, with movementlargely sustainedthrough unidirectional flow between adjacent countries.
Dr Javier Martin, the MHRA's Head of Polio Laboratory and a co-author of this paper, said:
"This study, whichexamines broad epidemiological patterns across multiple countries,providescrucial insights for targeting rapid response strategies and improvingpoliosurveillance.Understanding historical spread patterns helps predict and prevent future outbreaks as global polio eradication efforts continue."
Implications forglobalhealth
These findings have significant implications for outbreak response strategies. By understanding the speed and patterns of virus spread, health authorities can betteranticipategeographical reach when planning vaccination campaigns, potentially enabling more proactive preventive measures in neighbouring regions.
The study's lead researchers suggest that the current reactive approach-deploying vaccination campaigns following case detection-could be enhanced by considering preventive campaigns in neighbouring countries with low immunity levels.
Context
Vaccine-derived poliovirusemergesin rare instances when the weakened virus in oral polio vaccine mutates and regains the ability to cause paralysis. Whilst wild-type poliovirus has beenlargely eradicatedglobally, with type 1 now confined to just two countries (Pakistan and Afghanistan), cVDPV2 outbreaks have become a major challenge to complete polio eradication.
Since March 2021, a novel type-2 oral poliovirus vaccine (nOPV2), engineered to be more genetically stable.has been deployed under WHO Emergency Use Listing. The vaccine achieved full WHO prequalification in December 2023.Thenovel vaccine nOPV2was designed in large part by scientists at the MHRA.
ENDS
Notes to editors
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The Medicines and Healthcare products Regulatory Agency (MHRA)is responsible forregulating all medicines and medical devices in the UK by ensuring they work and are acceptably safe. All our work is underpinned by robust and fact-based judgements to ensure that the benefits justify any risks.
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The MHRA is an executive agency of the Department of Health and Social Care.
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The study was funded by the Bill and Melinda Gates Foundation and involved collaboration between Imperial College London, the MHRA, the Bill and Melinda Gates Foundation, and institutions in Belgium and Brazil.
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The World Health Organization continues to classify poliovirus spread as a Public Health Emergency of International Concern.
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For mediaenquiries, please contact thenewscentre@mhra.gov.uk, or call on020 3080 7651.
Disclaimer: Curated by HT Syndication.
