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Circulating vaccine-derived polioviruses (cVDPVs) can emerge and lead to outbreaks of paralytic polio as well as asymptomatic transmission in communities with a high percentage of under-vaccinated children. Data from the WHO Polio Information System (POLIS) and the Global Polio Laboratory Network (GPLN) are used below to describe global polio outbreaks due to cVDPVs during January 2023-June 2024. This updates previous reports. During the reporting period, 74 cVDPV outbreaks were detected in 39 countries, predominantly in Africa. Of the outbreaks, 47 (64%) were new and were detected in 30 (77%) of the 39 countries. Three countries reported cVDPV type 1 (cVDPV1) outbreaks; 39 reported cVDPV type 2 (cVDPV2) outbreaks; and 2 countries reported co-circulating cVDPV1 and cVDPV2. Seventy cVDPV2 outbreaks were reported in 38 countries. cVDPV transmission lasted for >1 year into 2024 in 15 countries. In Nigeria and Somalia, countries with security-compromised areas, persistent cVDPV2 transmission has spread to neighbouring countries. Delayed implementation of outbreak response and low-quality campaigns have resulted in further international spread. Countries can control cVDPV outbreaks with timely allocation of resources to implement prompt, high-quality responses after outbreak confirmation. Stopping cVDPV transmission requires vaccination to increase population immunity; this requires overcoming barriers to vaccinating children. Des emergences de poliovirus circulants derives d'une souche vaccinale (PVDVc) peuvent se produire et donner lieu a des flambees epidemiques de poliomyelite paralytique et a une transmission asymptomatique dans les communautes comptant une forte proportion d'enfants sous-vaccines. Le present rapport, qui est une mise a jour des rapports precedents, s'appuie sur les donnees du Systeme d'information de l'OMS sur la poliomyelite (POLIS) et du Reseau mondial de laboratoires pour la poliomyelite (RMLP) pour decrire les flambees epidemiques de poliomyelite dues aux PVDVc qui sont survenues dans le monde entre janvier 2023 et juin 2024. Au cours de la periode couverte par ce rapport, 74 flambees de PVDVc ont ete detectees dans 39 pays, principalement en Afrique. Parmi elles, on compte 47 (64%) flambees nouvelles, dans 30 (77%) des 39 pays. Trois pays ont signale des flambees dues aux PVDVc de type 1 (PVDVcl), 39 pays ont notifie des flambees de PVDVc de type 2 (PVDVc2) et 2 pays ont fait etat d'une cocirculation de PVDVcl et de PVDVc2. Les flambees de PVDVc2 signalees dans 39 pays etaient au nombre de 70. Dans 15 pays, la transmission des PVDVc a dure >1 an, se poursuivant en 2024. Au Nigeria et en Somalie, pays dont certaines zones sont en proie a des problemes de securite, la transmission persistante des PVDVc2 s'est etendue aux pays voisins. La mise en oeuvre tardive des activites de riposte et la faible qualite des campagnes ont conduit a une propagation internationale supplementaire. Les flambees epidemiques de PVDVc peuvent etre endiguees rapidement si les pays deploient en temps utile les ressources necessaires a la mise en oeuvre d'une riposte rapide et de qualite une fois que l'epidemie est confirmee. Pour interrompre la transmission des PVDVc, il est essentiel d'accroitre l'immunite de la population grace a la vaccination, ce qui suppose de surmonter les obstacles qui entravent la vaccination des enfants., Introduction Live, attenuated oral poliovirus vaccine (OPV) induces long-term protection against paralytic disease and limits virus shedding in vaccinated people who are infected. (1) Circulating vaccine-derived polioviruses (cVDPVs) (2) occur [...]

The reliable and timely detection of poliovirus infection through surveillance for acute flaccid paralysis (AFP), supplemented by environmental surveillance (ES) of sewage samples, is a critical component of the polio eradication programme. Since 1988, the number of polio cases caused by wild poliovirus (WPV) has decreased by >99.9%, and eradication of WPV serotypes 2 and 3 has been certified; only serotype 1 (WPV1) continues to circulate and transmission remains endemic in Afghanistan and Pakistan. In this surveillance update, we evaluated indicators of AFP in surveillance, ES for polioviruses and data on the performance of the Global Polio Laboratory Network (GPLN) provided by 28 priority countries for the programme during 2022-2023. No WPV1 cases have been detected outside those countries since August 2022, when importation into Malawi and Mozambique resulted in an outbreak during 2021-2022. During 2022-2023, 20 of 28 priority countries (71.4%) met national AFP surveillance indicator targets, and the number of ES sites increased. Low national rates of reported AFP cases in priority countries in 2023 might have been due to lags in surveillance reporting; substantial national and subnational AFP surveillance gaps persist. Maintaining high-quality surveillance is critical to achieving the goal of global polio eradication. Monitoring surveillance indicators is important to identifying gaps and guiding surveillance-strengthening activities, particularly in countries at high risk for poliovirus circulation. La detection fiable et rapide de l'infection a poliovirus au moyen de la surveillance de la paralysie flasque aigue (PFA), completee par une surveillance des echantillons d'eaux usees, est un element essentiel du programme d'eradication de la poliomyelite. Depuis 1988, le nombre de cas de poliomyelite dus au poliovirus sauvage (PVS) a diminue de >99,9% et l'eradication des serotypes 2 et 3 du PVS a ete certifiee; seul le serotype 1 du poliovirus sauvage (PVS1) continue de circuler et la transmission demeure endemique en Afghanistan et au Pakistan. Dans ce rapport faisant le point sur la surveillance, nous evaluons les indicateurs de la PFA a des fins de surveillance pour la recherche des poliovirus et les donnees relatives aux performances du Reseau mondial de laboratoires pour la poliomyelite (RMLP) communiquees par les 28 pays prioritaires pour le programme en 2022-2023. Aucun cas du au PVS1 n'a ete detecte en dehors de ces pays depuis aout 2022, apres une flambee epidemique en 2021-2022 due a l'importation du virus au Malawi et au Mozambique. En 2022-2023, 20 des 28 pays prioritaires (71,4 %) ont atteint les cibles des indicateurs de surveillance de la PFA, et le nombre de sites de surveillance environnementale a augmente. Le faible nombre de cas de PFA signales dans les pays prioritaires en 2023 pourrait etre du a des retards dans la communication des donnees issues de la surveillance; d'importantes lacunes en matiere de surveillance de la PFA a l'echelle nationale et infranationale persistent. Il est essentiel de maintenir une surveillance de qualite afin d'atteindre l'eradication de la poliomyelite a l'echelle mondiale. Un suivi des indicateurs de surveillance est egalement important pour identifier les lacunes et orienter les activites de surveillance, particulierement dans les pays oU il existe un risque eleve de circulation du poliovirus., Introduction Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of WPV cases has decreased by >99.9%, and WPV serotypes 2 and 3 have been declared [...]

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was reported in 125 countries. Since 2017, Afghanistan and Pakistan have been the only countries with uninterrupted endemic WPV type 1 (WPV1) transmission. This report describes activities and progress towards polio eradication in Afghanistan during January 2022-June 2023. Two WPV1 cases were reported during January-December 2022 and 5 during January-June 2023 (as of 26 August), all in 3 provinces in the Southeast and East regions bordering Pakistan. All 5 cases in 2023 had reportedly received [greater than or equal to] 16 oral poliovirus vaccine doses. WPV1 was detected in sewage samples from a site in the South Region in May 2023 and one in the North Region in June 2023, the first detections since February 2021 and March 2020, respectively. Restrictions on house-to-house vaccination limit the effectiveness of vaccination campaigns in parts of the South and Northeast regions. Because of population movement, the risk for transmission in Afghanistan and Pakistan will remain if WPV1 circulation continues in either country. Despite operational improvements in vaccination activities, interruption of WPV1 transmission in Afghanistan will require committed, uninterrupted efforts to address vaccination coverage gaps that sustain WPV1 circulation, including ongoing coordination with Pakistan on polio eradication activities. Lorsque l'Initiative mondiale pour l'eradication de la poliomyelite (IMEP) a debute en 1988, la transmission du poliovirus sauvage (PVS) concernait 125 pays. Depuis 2017, l'Afghanistan et le Pakistan sont les seuls pays oU il existe encore une transmission endemique ininterrompue du PVS de type 1 (PVS1). Le present rapport decrit les activites et les progres accomplis vers l'eradication de la poliomyelite en Afghanistan entre janvier 2022 et juin 2023. Deux cas de PVS1 ont ete signales entre janvier et decembre 2022 et 5 entre janvier et juin 2023 (donnees au 26 aout), tous situes dans 3 provinces des regions du sud-est et de l'est, a la frontiere du Pakistan. Les 5 cas notifies en 2023 auraient recu >16 doses de vaccin antipoliomyelitique oral. Le PVS1 a ete detecte dans des echantillons d'eaux usees preleves sur un site de la region sud en mai 2023 et un autre dans la region nord en juin 2023, les premieres detections depuis fevrier 2021 et mars 2020, respectivement. Les restrictions sur la vaccination porte-a-porte limitent l'efficacite des campagnes de vaccination dans certaines parties des regions du sud et du nord-est. En raison des mouvements de population, le risque de transmission en Afghanistan et au Pakistan subsistera si le PVS1 continue de circuler dans l'un ou l'autre pays. Malgre l'amelioration des activites de vaccination sur le plan operationnel, l'interruption de la transmission du PVS1 en Afghanistan necessitera des efforts resolus et ininterrompus pour combler les lacunes de la couverture vaccinale qui permettent au PVS1 de continuer de circuler, y compris une coordination constante avec le Pakistan sur les activites d'eradication de la poliomyelite., Introduction Worldwide, the number of cases due to WPV has decreased by more than 99.9% since the Global Polio Eradication Initiative (GPEI) commenced in 1988, and global eradication of indigenous [...]

Since the Global Polio Eradication Initiative was established in 1988, the number of cases due to wild poliovirus (WPV) has decreased by >99.9%, and WPV serotypes 2 and 3 have [...]

Since the Global Polio Eradication Initiative (GPEI) began in 1988, the number of cases due to wild poliovirus (WPV) has decreased by > 99.99%. Five of the 6 WHO regions [...]

An outbreak of circulating vaccine-derived poliovirus (cVDPV) (1) can occur when oral poliovirus strains (OPV, containing [greater than or equal to] 1 Sabin-strain serotypes 1, 2 and 3) circulate for [...]

Afghanistan and Pakistan are the 2 remaining countries with endemic wild poliovirus type 1 (WPV1) transmission. (1) During 2019-2020, these countries reported the highest numbers of WPV1 cases since 2014 [...]

Pakistan reported a single case of polio associated with wild poliovirus type 1 (WPV1) in 2021 but reported 14 cases between 1 April and 31 July 2022. Afghanistan and Pakistan [...]

The emergence and international spread of neurovirulent circulating vaccine-derived polioviruses (cVDPVs) throughout many countries in Africa and Asia in recent years pose a major challenge to the goal of eradicating [...]

In 1988, the World Health Assembly established the Global Polio Eradication Initiative (GPEI). Since then, wild poliovirus (WPV) cases have decreased approximately 99.99%, and WPV types 2 and 3 have [...]

Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of reported poliomyelitis cases worldwide has decreased by approximately 99.99%. By the end of 2021, wild poliovirus [...]

Wild poliovirus types 2 and 3 were declared eradicated in 2015 and 2019, respectively, and, since 2017, transmission of wild poliovirus type 1 (WPV1) has been detected only in Afghanistan [...]

As of 1 May 2016, the use of oral poliovirus vaccine (OPV) type 2 for routine and supplementary immunization activities (SIAs) ceased after a synchronized global switch from trivalent OPV [...]

When the Global Polio Eradication Initiative (GPEI) began in 1988, wild poliovirus (WPV) was being transmitted in 125 countries; currently, transmission of WPV type 1 (WPV1) continues in only 2 [...]

When the Global Polio Eradication Initiative (GPEI) was established in 1988, an estimated 350 000 poliomyelitis cases were reported worldwide. In 2020, 140 wild poliovirus (WPV) cases were confirmed, representing [...]

Afghanistan and Pakistan are the only countries with ongoing transmission of wild poliovirus type 1 (WPV1). (1, 2) In 2019, Pakistan reported 147 cases due to WPV1, 12 times the [...]

Wild poliovirus type 1 (WPV1) is still being transmitted only in Afghanistan and Pakistan. (1) After decreases in the numbers of cases in Afghanistan during 2013-2016, the number increased each [...]

Since establishment of the Global Polio Eradication Initiative (1) in 1988, the number of polio cases worldwide has decreased by >99.9%. Extensive use of live attenuated oral poliovirus vaccine (OPV) [...]

Since the Global Polio Eradication Initiative (GPEI) was launched in 1988, the number of polio cases worldwide has decreased by over 99.99%; only 2 countries, Afghanistan and Pakistan, have never [...]

Circulating vaccine-derived polioviruses (cVDPVs) can emerge in areas with low poliovirus immunity and cause outbreaks (1) of paralytic polio. (2-6) Of the 3 types of wild poliovirus, type 2 was [...]

The reliable and timely detection of poliovirus cases through surveillance for acute flaccid paralysis (AFP), supplemented by environmental surveillance of sewage samples, is a critical component of the polio eradication program. Since 1988, the number of polio cases caused by wild poliovirus (WPV) has declined by >99.9%, and eradication of WPV serotypes 2 and 3 has been certified; only serotype 1 (WPV1) continues to circulate, and transmission remains endemic in Afghanistan and Pakistan. This surveillance update evaluated indicators from AFP surveillance, environmental surveillance for polioviruses, and Global Polio Laboratory Network performance data provided by 28 priority countries for the program during 2022-2023. No WPV1 cases have been detected outside of Afghanistan and Pakistan since August 2022, when an importation into Malawi and Mozambique resulted in an outbreak during 2021-2022. During 2022-2023, among 28 priority countries, 20 (71.4%) met national AFP surveillance indicator targets, and the number of environmental surveillance sites increased. However, low national rates of reported AFP cases in priority countries in 2023 might have resulted from surveillance reporting lags; substantial national and subnational AFP surveillance gaps persist. Maintaining high-quality surveillance is critical to achieving the goal of global polio eradication. Monitoring surveillance indicators is important to identifying gaps and guiding surveillance-strengthening activities, particularly in countries at high risk for poliovirus circulation. [ABSTRACT FROM AUTHOR]

Afghanistan and Pakistan are the only countries that continue to confirm transmission of wild poliovirus type 1 (WPV1). (1) This report on the status of polio eradication and progress in [...]

Global eradication of indigenous wild poliovirus type 2 was certified in 2015 and that of type 3 in 2019. Since the launch of the Global Polio Eradication Initiative (GPEI) in [...]

Since October 2016, Afghanistan and Pakistan have been the only 2 countries to report cases of polio due to wild poliovirus type 1 (WPV1). (1) In Afghanistan, although the number [...]

Afghanistan, Nigeria and Pakistan remain endemic for wild poliovirus type 1 (WPV1). (1) Polio eradication activities decreased the number of confirmed WPV cases in Nigeria to 6 by July 2014, [...]

When the Global Polio Eradication Initiative (GPEI) began in 1988, cases of poliomyelitis were reported from 125 countries. Currently, only Afghanistan, Nigeria and Pakistan have never interrupted wild poliovirus (WPV) [...]