Rare recurrences of poliomyelitis in non-endemic countries after eradication: a call for global action

Abstract

Following the confirmation on July 21, 2022, of a case of poliomyelitis related to circulating vaccine-derived poliovirus (cVDPV) type 2 in an unvaccinated adult from Rockland County, NY, USA,1PAHOEpidemiological alert: detection of vaccine-derived poliovirus type 2 (VDPV2) in the United States: implications for the region of the Americas—21 July 2022.http://www.paho.org/en/documents/epidemiological-alert-detection-vaccine-derived-poliovirus-type-2-vdpv2-united-statesDate: 2022Date accessed: July 30, 2022Google Scholar there has been a renewed global drive to strengthen surveillance for the detection of cases and increase vaccination coverage against polio. This is the first known case of polio with paralysis in nearly a decade in the USA, a country that no longer administers the oral polio vaccine, which suggests that the virus could have been imported. The US Centres for Disease Control and Prevention reported discovering the poliovirus in a New York suburb's wastewater in June, 2022, before detecting the case in July, which suggests that people were shedding the virus in their stool. In the UK, a national incident was declared in late June, 2022, following the discovery of related poliovirus strains with mutations in sewage samples collected from north London and east London,2WHOVaccine-derived poliovirus type 2 (VDPV2) detected in environmental samples in London, UK.http://www.who.int/news/item/22-06-2022-vaccine-derived-poliovirus-type-2-(vdpv2)-detected-in-environmental-samples-in-london--ukDate: 2022Date accessed: July 30, 2022Google Scholar signifying that the virus had also spread between individuals. In March, 2022, cVDPV type 3 was confirmed in an unvaccinated child from Jerusalem, Israel. Laboratory tests revealed the viral strain in the patient in the USA and the sewage samples in the UK were genetically related to the strain found in Israel. Similarly, in October, 2021, Ukraine confirmed a case of polio in a child aged 18 months in Rivne Orblast, caused by cVDPV type 2, after almost 10 years of polio eradication in Europe. The live-attenuated poliovirus received through vaccination can spread between people. In unvaccinated people, mutations can be produced that can lead to a manifestation of cVDPV disease. Additionally, polio outbreaks in non-endemic countries can arise from travelling and importation from endemic countries, as has occurred in Israel, Tajikistan (bordered by Afghanistan, China, and Uzbekistan), and in Malawi and Mozambique. It is important to underline that the patient with poliomyelitis in New York had not travelled to countries endemic for polio. Poliovirus is highly infectious. Although faecal-oral transmission was assumed to be the most relevant route, it spreads mainly through respiratory droplets,3John TJ Dharmapalan D Challenges en route to polio eradication.Lancet. 2022; 400: 428-429Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar and affects the nervous system causing paralysis, which can lead to permanent disability and death. As a result of the vaccination and surveillance programmes led by the Global Polio Eradication Initiative (GPEI), the number of wild poliovirus cases has decreased by more than 99% since 1988. The Americas was the first region to be certified polio-free by WHO in 1994, followed by the Western Pacific (2000), Europe (2002), South-East Asia (2015), and finally Africa (2020).4WHOPolio eradication strategy 2022–2026: delivering on a promise.http://www.who.int/publications/i/item/9789240031937Date: 2021Date accessed: July 30, 2022Google Scholar Yet, despite the outstanding progress towards global eradication, the fight against poliovirus is far from over, given the continuing endemicity of the wild poliovirus (type 1) in Afghanistan and Pakistan. Additionally, cVDPV is a growing problem that threatens global eradication efforts.5Venkatesan P Global polio eradication set back by COVID-19 pandemic.Lancet Microbe. 2022; 3: e172Summary Full Text Full Text PDF PubMed Google Scholar Outbreaks of cVDPV are usually reported in politically unstable countries, where inactivated poliovirus immunisation is interrupted and oral polio vaccine is administered to vulnerable populations with low immunity. This raises questions about cVDPV triggering rare reoccurrences of polio in politically stable non-endemic countries, such as the UK and USA. It is unclear to what extent the recurrence of polio in both countries are linked to COVID-19-related slowdown of polio vaccination and surveillance, which caused outbreaks of cVDPVs in 37 countries globally, 1412 detections of cVDPVs through environmental surveillance, and 1335 detections of cVDPVs in stool samples of patients with acute flaccid paralysis globally.6Wilkinson AL Diop OM Jorba J Gardner T Snider CJ Ahmed J Surveillance to track progress toward polio eradication—worldwide, 2020–2021.MMWR Morb Mortal Wkly Rep. 2022; 71: 538-544Crossref PubMed Google Scholar Other emergencies that increase the risk of polio spread include the ongoing war in Ukraine and instability in Israel, Afghanistan, Pakistan, and the African region. Moreover, a growing anti-vaccine movement is contributing to reducing vaccination rates in high-income countries.7Roberts HA Clark DA Kalina C et al.To vax or not to vax: predictors of anti-vax attitudes and COVID-19 vaccine hesitancy prior to widespread vaccine availability.PLoS One. 2022; 17: e0264019Crossref PubMed Scopus (37) Google Scholar, 8Ward JK Verger P MacDonald NE Dubé ÈVaccine hesitancy, acceptance, and anti-vaccination: trends and future prospects for public health.Annu Rev Public Health. 2021; 42: 175-191Crossref PubMed Scopus (154) Google Scholar, 9Pandolfi F Franza L Todi L et al.The importance of complying with vaccination protocols in developed countries: “anti-vax” hysteria and the spread of severe preventable diseases.Curr Med Chem. 2018; 25: 6070-6081Crossref PubMed Scopus (24) Google Scholar The strategy of deploying live-attenuated poliovirus-based vaccines instead of the inactivated poliovirus vaccines is being questioned, due to the rise in cVDPV transmission. In 2020, a modified polio vaccine, the type 2 novel oral polio vaccine (nOPV2), received emergency approval from WHO for preventing outbreaks of cVDPV in African and eastern Mediterranean countries. Since March, 2021, more than 300 million doses of nOPV2 have been administered in 15 countries globally.10GPEIcVDPV2 outbreaks and the type 2 novel oral polio vaccine (nOPV2). Global Polio Eradication Initiative, Washington, DC2022Google Scholar It is time to increase production, distribution, and administration of nOPV2, to address the increasing rates of cVDPV in both endemic and non-endemic countries, and promote a robust wastewater surveillance system. Polio eradication efforts in Pakistan, Afghanistan, and other politically unstable regions should be escalated to mitigate the untoward consequences of lower vaccination coverage. All counties should anticipate and aim to counteract growing anti-vaccine attitudes or hesitancy to vaccination, to reduce the spread of polio and other communicable diseases. We declare no competing interests.

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