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The article reports on the updates on vaccine-derived poliovirus outbreaks around the world from January 2020 to June 2021. Also cited are how prolonged transmission of Sabin strain poliovirus could cause circulating vaccine-derived poliovirus (cVDPV) outbreaks, the goal of the Global Polio Eradication Initiative's (GPEI) 2022-2026 Strategic Plan, and the discovery of cVDPVl-linked poliovirus in Malaysia.

The article provides an update on global circulating vaccine-derived polioviruses (cVDPV) outbreaks from July 2019 to February 2020. Highlights include the plan of the Global Polio Eradication Initiative to introduce a genetically-stabilized novel oral poliovirus vaccine type 2, isolation of genetically-linked virus from sewage samples in Sabah State, Malaysia in June and November 2019, and the number of Central African countries affected by cVDPV2 outbreaks during July 2019 to February 2020.

The article provides data on circulating vaccine-derived poliovirus (cVDPV) outbreaks detected from January 2018 to June 2019. Highlights include cessation of use of all oral poliovirus vaccines (OPV) after certification of polio eradication, an outline of cVDPVs worldwide detected by serotype and other selected attributes, and OPV coverage in Central African Republic before and after the switch from trivalent OPV and bivalent OPV.

The article presents an update on the implementation of the Global Polio Eradication Initiative, particularly the use of live attenuated oral polio vaccine (OPV), to eliminate polio worldwide as of June 2018. Also cited are the few cases of genetically divergent vaccine-derived polioviruses (VDPV) during the national routine immunization schedules and mass vaccination programs, as well as the possible emergence of circulating VDPV (cVDPV) and immunodeficiency VDPV (iVDPV) in low coverage areas.

The article provides an update on vaccine-derived polioviruses (VDPV) worldwide from January 2016 to June 2017. Topics covered include the 2015-2016 outbreak in Lao People's Democratic Republic, properties and virological characterization of VDPVs, and a decrease in the number of countries with detected circulation of VDPVs from January 2016 to June 2017.

The article presents an update on surveillance summaries of poliomyelitis and describes vaccine-derived polioviruses (VDPVs) detected worldwide from January 2015-May 2016. Topics discussed include difference between VDPVs and vaccine-associated paralytic poliomyelitis (VAPP), VDPV properties and its virological testing, and VDPV circulation, particularly new outbreaks in circulating VDPVs (cVDPV) in Myanmar, Lao People's Democratic Republic, Ukraine and Guinea.

ABSTRACTFrom March to May 2006, type 1 circulating vaccine-derived poliovirus (cVDPV) was isolated from one case patient with acute flaccid paralysis (AFP) and six unimmunized healthy contacts in isolated mountain villages in Guangxi, China. We conducted epidemiological investigations in the affected communities and nucleotide sequence analyses of the cVDPV isolates. The results of the investigations showed that the AFP patient, an unimmunized 10-year-old boy, and five laboratory-confirmed contacts lived in the same village; one contact lived in a neighboring village. Only ~27% of children 5 to 10 years of age in the affected villages had received three or more doses of the trivalent oral poliovirus vaccine (OPV). Nucleotide sequence analyses revealed that the cVDPV isolates differed from the Sabin 1 (S1) isolate at 1.4 to 2.2% of VP1 nucleotide positions and shared 12 nucleotide substitutions within VP1. All isolates were S1/S2/S1/S3 recombinants sharing common recombination junctions. Key determinants of attenuation were replaced. Phylogenetic analysis suggested that the cVDPV circulated locally for ~12 months following the initiating OPV dose. No VDPVs were found after mass OPV immunizations, conducted from May to June 2006, that targeted all children <12 years of age. Our findings reinforce the point that VDPVs can emerge and spread in isolated communities with immunity gaps. Maintenance of sensitive AFP and poliovirus surveillance is essential to permit early detection and a rapid response to VDPV circulation.

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. [ABSTRACT FROM AUTHOR]

The article discusses the genetic characterization of the novel oral polio vaccine type 2 (nOPV2) viruses by the World Health Organization (WHO) during the initial use phase of the vaccine worldwide in March-October 2021. The vaccine was aimed at eradicating neurovirulent circulating vaccine-derived polioviruses (cVDPV), particularly in Africa and Asia. Also cited is the Sabin vaccine as the main cause of cVDPV outbreaks.

The article reports on the progress and accomplishments in the implementation of the Global Polio Eradication Initiative (GPEI) by the World Health Organization (WHO). Topics include the detection of circulating vaccine-derived poliovirus (cVDPV) infections in 31 countries in 2020-2021 through surveillance for acute flaccid paralysis (AFP) and how the COVID-19 pandemic disrupted polio vaccination.

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. [ABSTRACT FROM AUTHOR]

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 ≥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-tohouse 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. [ABSTRACT FROM AUTHOR]

The article presents poliovirus surveillance data from 2016 to 2017, with particular focus on 20 countries in the African Region and six in the Eastern Mediterranean Region. Topics mentioned include two principal indicators that measure the quality of acute flaccid paralysis (AFP) surveillance, poliovirus transmission that might occur in the absence of detected AFP cases, and an increase in environmental surveillance collection sites in Afghanistan, Nigeria, and Pakistan from 2011 to 2017.

Since establishment of the Global Polio Eradication Initiative (GPEI) in 1988, Pakistan is 1 of only 2 countries (with Afghanistan) that has continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress towards polio eradication during January 2022-June 2023. In 2022, Pakistan reported 20 cases due to WPV type 1 (WPV1), all of which occurred in the small geographical area encompassing 3 districts in south Khyber Pakhtunkhwa. As of 23 June 2023, only 1 WPV1 case had been reported, in Bannu district in Khyber Pakhtunkhwa province, as compared with 13 cases during the same period in 2022. Eleven WPV1 isolates from environmental surveillance (ES) sewage sampling sites have been reported to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographical scope of poliovirus circulation in Pakistan, isolation of WPV1 from an ES site in Karachi raises concern about the actual geographical limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained, innovative work to vaccinate children who are regularly missed during SIAs and rapid response to any new WPV1 isolations. [ABSTRACT FROM AUTHOR]

The article provides updates on previous reports and describes surveillance performance on poliomyelitis eradication during 2021-2022 in 34 priority countries. Topics discussed include surveillance of acute flaccid paralysis, national and subnational acute flaccid paralysis (AFP) surveillance performance indicators and number of confirmed cases of poliomyelitis due to wild poliovirus (WPV) and circulating vaccine-derived poliovirus cases, and information on the Global Polio Laboratory Network.

The article offers information on the progress of surveillance systems towards poliovirus eradication from 2015 to 2016. Topics discussed include how the quality of acute flaccid paralysis (AFP) surveillance is measured, components of the Global Polio Laboratory Network (GPLN), and the lowest cases of wildlife poliovirus (WPV) in 2016.

The article presents an update on the outbreak of wild poliovirus (WPV) type 1 in southeastern Africa for the years 2021-2022. Topics discussed include detection of WPV1 during November 2021-December 2022, and as of April 7, 2023, routine immunization in the region, and two core acute flaccid paralysis (AFP) surveillance performance indicators.

The article presents updates on the vaccine-derived poliovirus (cVDPV) outbreaks worldwide from January 2021 to December 2022 and the efforts by the World Health Organization in addressing the virus. Other topics include the oral poliovirus Sabin-strain type 2 (OPV2) removal from routine immunization (RI) activities and the preventive immunization campaigns during the coronavirus disease (COVID-19) pandemic.

The article outlines the progress towards poliomyelitis eradication in Afghanistan from January 2021 to September 2022. It reports immunization with oral poliovirus vaccine and inactivated poliovirus vaccine among children, as well as acute flaccid paralysis surveillance and environmental surveillance as supplements to poliovirus surveillance. Data shows the epidemiology of polio cases and genomic sequence analysis of poliovirus isolates including evidence of cross-border transmission.

The article discusses the activities, challenges, and progress in the efforts to eradicate poliomyelitis (polio) in Pakistan from January 2015 to September 2016. Also cited are the number of wild poliovirus type 1 (WPV1) cases in 2015, the implementation of the 2015-2016 Pakistan National Emergency Action Plan (NEAP) for polio eradication, and the role of the National Emergency Operation Center (EOC) in the program.

The article reports on the status of the strategic plan of the Global Polio Eradication Initiative in Pakistan from January 2021 to July 2022. Topics mentioned include the re-emergence of wild poliovirus type 1 transmission from April 1 2022 to July 2022, the number of children who failed to participate in the nationwide polio supplementary immunization activities, the epidemiology of poliomyelitis cases, and the environmental and acute flaccid paralysis surveillance of poliovirus.

The article reports on the accomplishments by the World Health Assembly in eradicating polio around the world from January 2020 to April 2022 under its Global Polio Eradication Initiative (GPEI). Topics include the eradication of wild poliovirus (WPV) types 2 and 3 cases around the world, the decline of WPV 1 cases in Afghanistan and Pakistan, and the emergence of circulating vaccine-derived polioviruses (cVDPV).

The article presents an update on the progress of the implementation of health programs from January 2020 to November 2021 for the eradication of poliomyelitis in Afghanistan. Topics include the outbreaks of type 2 circulating vaccine-derived poliovirus (cVDPV2) in the country and the oral poliovirus vaccine (OPV) campaigns to vaccinate children against poliovirus.

The article reports on the accomplishments of the polio eradication program in Pakistan from January 2020 to July 2021. Topics include the number of wild poliovirus (WPV) infections in the country, the Global Polio Eradication Initiative (GPEI) launched in 1988, and the emergence of circulating vaccine-derived poliovirus (cVDPV) due to regained neurovirulence of attenuated vaccine-derived poliovirus (cVDPV).

The article reports on the accomplishments of the World Health Organization (WHO) in eradicating polio around the world under the Global Polio Eradication Initiative (GPEI) as of May 2021. Topics include the recorded cases of poliomyelitis worldwide since 1988 and the use of syndromic surveillance for acute flaccid paralysis (AFP) to detect poliovirus transmission among children under 15 years old.

The article provides an update on immunodeficiency-associated vaccine-derived polioviruses (iVDPV) worldwide from July 2018 to December 2019. Topics discussed include surveillance for acute flaccid paralysis and for poliovirus infections among patients with primary immunodeficiency, classification of vaccine-derived polioviruses, and summary of iVDPV epidemiology from 1961 to 2019.

The article reports on the status of polio eradication and progress in Pakistan from January 2018 to September 2019. Highlights include assessment of the quality of supplementary immunization activities (SIAs) in subdistricts, implementation of SIA rounds with a single dose of injectable inactivated poliovirus vaccine, and community-based vaccination and permanent transit points.

The article describes polio eradication activities and progress in Afghanistan between January 2018 and May 2019. Topics include authorization of vaccination of children at designated community sites from January to April 2019, the standard supplementary immunization activity (SIA) approach for polio eradication, and the use of low quality assurance sampling surveys to examine the quality of SIAs in areas where post-campaign monitoring is permitted.

The article describes the progress in polio eradication in Nigeria between January 2018 and May 2019. Topics covered include insurgency in Borno, Adamawa, and Yobe states in 2009 that led to internal displacement of 1.8 million people in Nigeria, national coverage with a third dose of poliovirus vaccine by year of age delivered by routine childhood immunization services, and two major indicators of poliovirus transmission.

The article examines Pakistan's activities and progress towards polio eradication from January 2017 to September 2018 and provides updates on previous reports. Pakistan reported eight cases due to wild poliovirus type 1 in 2017. Nine nationwide supplementary immunization activities (SIAs) and eight sub-national SIAs were done with bivalent oral poliovirus vaccine (OPV). The frequency of parental refusal of OPV vaccination has increased despite advances in past years.

The article reports on the transmission of circulating vaccine-derived poliovirus (PV) identified by environmental surveillance and immunization response in Horn of Africa from 2017 to 2018. Sixteen environmental PV surveillance sites have been established to supplement acute flaccid paralysis surveillance. Two vaccination response campaigns with monovalent oral PV type 2 were done in December 2017 and January 2018. A limited response vaccination campaign was done in Nairobi in May 2018.

The article describes polio eradication activities and progress in and challenges to eradication in Afghanistan from January 2017 to May 2018. Highlights include the number of cases of polio due to wild poliovirus type 1 in the country in 2017, an increase in the number of polio-affected districts from 2016 to 2017, and national routine vaccination coverage of infants with three doses of oral poliovirus vaccine in Afghanistan in 2015 and 2016.

The article describes global progress towards polio eradication between January 2016 and March 2018 and provides updates on previous reports. Topics mentioned include continuing wild poliovirus (WPV) type 1 transmission in Pakistan in samples isolated from wastewater, how WPV transmission can be interrupted, and the number of supplementary vaccination activities conducted in five World Health Organization regions in 2016.

The article describes activities done and progress made towards the eradication of poliovirus in Pakistan from January 2016 to September 2017. Topics covered include a decrease in wild poliovirus type 1 cases in the country from 2015 to 2016, the national routine vaccination coverage among infants with three doses of oral poliovirus vaccines in 2016, and percentage of zero-dose children in the province of Balochistan from 2016 to 2017.

The article focuses on endemic wild poliovirus (WPV) transmission in security-compromise areas in Nigeria in 2016, specifically in Borno State. Topics discussed include the low population immunity and severe surveilance limitations associated with insurgency-related insecurity and the risk for local and international WPV spread in Borno, the identified cases of WPV in Borno, and supplementary immunization activities in the state.

The article reports on the progress of polio eradication efforts in Afghanistan from January 2015 to August 2016. Topics covered include reports on cases of wild poliovirus type 1 (WPV1), non-polio acute flaccid paralysis (NPAFP) in children and dosage of oral poliovirus vaccine (OPV) in supplementary immunization services (SIAs). Also mentioned are activities during national immunization days (NIDs), liquid quality assurance sampling (LQAS) and vaccine-derived poliovirus (VDPV) epidemiology.

The article discusses the environmental isolation of a vaccine-derived poliovirus type 2 (VDPV2) collected from a sewage effluent site in Maiduguri Municipal Council in Nigeria on April 29, 2016. Topics discussed include its viral lineage responsible for circulating VDPV2 (cVDPV2) outbreak in several countries in 2012-2014, and outbreak response standard operating procedures including supplemental immunization activities (SIAs) activated by Nigeria National Polio Emergency Operations Center.