Search

Since its launch in 1988, the Global Polio Eradication Initiative has made substantial progress toward the eradication of wild poliovirus (WPV), including eradicating two of the three serotypes, and reducing the countries with ongoing endemic transmission of WPV type 1 (WPV1) to just Afghanistan and Pakistan. Both countries are considered a single epidemiologic block. Despite the occurrence of only a single confirmed WPV1 case during the first half of 2023, Pakistan experienced widespread circulation of WPV1 over the subsequent 12 months, specifically in the historical reservoirs of the cities of Karachi, Peshawar, and Quetta. As of June 30, 2024, eight WPV1 cases had been reported in Pakistan in 2024, compared with six reported during all of 2023. These cases, along with more than 300 WPV1-positive environmental surveillance (sewage) samples reported during 2023-2024, indicate that Pakistan is not on track to interrupt WPV1 transmission. The country's complex sociopolitical and security environment continues to pose formidable challenges to poliovirus elimination. To interrupt WPV1 transmission, sustained political commitment to polio eradication, including increased accountability at all levels, would be vital for the polio program. Efforts to systematically track and vaccinate children who are continually missed during polio vaccination activities should be enhanced by better addressing operational issues and the underlying reasons for community resistance to vaccination and vaccine hesitancy., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Social science research on polio has been centred in the global south, where countries that remain endemic or vulnerable to outbreaks are located. However, closely-related strains of poliovirus were detected in the sewage systems of several New York State counties and London boroughs in 2022. These detections constituted the first encounters with polio in the United States and United Kingdom for a generation - for both public health agencies and publics alike. This paper takes the transnational spread of poliovirus in 2022 as an opportunity to critique how public health memories of twentieth-century polio epidemics were mobilised to encourage vaccine uptake among groups considered vulnerable to transmission, notably Orthodox Jewish families. The study integrates data collected in London and New York as part of academic engagement with health protection responses to the spread of polio. Methods in both settings involved ethnographic research, and a total of 59 in-depth semi-structured interviews with public health professionals, healthcare providers, and Orthodox Jewish community partners and residents. Analysis of results demonstrate that narratives of epidemiological progress were deployed in public health responses in London and New York, often through references to sugar cubes, iron lungs, and timelines that narrate the impact of routine childhood immunisations. While memories of polio were deployed in both settings to provoke an urgency to vaccinate, vulnerable publics instead considered the more recent legacy of the COVID-19 pandemic when deciding whether to trust recommendations and responses. Critical attention to memory places analysis on the divergences between institutional (public health agencies) and peopled (publics) responses to disease events. Responses to re-emerging infectious disease outbreaks engender a temporal dissonance when historical narratives are evoked in ways that contrast with the contemporary dilemmas of people and parents., Competing Interests: Declaration of competing interest None of the authors declare any conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Poliovirus is a highly infectious enterovirus (EV) that primarily affects children and can lead to lifelong paralysis or even death. Vaccine-derived polioviruses (VDPVs) are a great threat since they are derived from the attenuated virus in the Oral Poliovirus Vaccine (OPV) and can mutate to a more virulent form. The purpose of this study was to identify VDPV serotype 2 through the year 2020-2021 via surveillance of sewage samples collected from different localities and governorates in Egypt and stool specimens from Acute Flaccid Paralysis (AFP) cases. Both were collected through the national poliovirus surveillance system and according to the guidelines recommended by the WHO., Methods: A total of 1266 sewage samples and 3241 stool samples from January 2020 to December 2021 were investigated in the lab according to World Health Organization (WHO) protocol for the presence of Polioviruses by cell culture, molecular identification of positive isolates on L20B cell line was carried out using real-time polymerase chain reactions (RT-PCR). Any positive isolates for Poliovirus type 2 and isolates suspected of Vaccine Derived Poliovirus Type 1 and type 3 screened by (VDPV1) or Vaccine Poliovirus Type 3 (VDPV3) assay in RT-PCR were referred for VP1 genetic sequencing., Results: The outbreak was caused by circulating VDPV2 (cVDPV2) strains started in January 2021. By the end of February 2021, a total of 11 cVDPV2s were detected in sewage samples from six governorates confirming the outbreak situation. One additional cVDPV2 was detected later in the sewage sample from Qena (June 2021). The first and only re-emergence of VDPV2 in stool samples during the outbreak was in contact with Luxor in June 2021. By November 2021, a total of 80 VDPVs were detected. The Egyptian Ministry of Health and Population (MOHP), in collaboration with the WHO, responded quickly by launching two massive vaccination campaigns targeting children under the age of five. Additionally, surveillance systems were strengthened to detect new cases and prevent further spread of the virus., Conclusion: The continued threat of poliovirus and VDPVs requires ongoing efforts to prevent their emergence and spread. Strategies such as improving immunization coverage, using genetically stable vaccines, and establishing surveillance systems are critical to achieving global eradication of poliovirus and efficient monitoring of VDPVs outbreaks., (© 2024. The Author(s).)

Despite a half-century-long global eradication effort, polio continues to have a devastating impact on individuals and communities worldwide, especially in low-income countries affected by conflict or geographic barriers to immunization programs. In response, the World Health Organization (WHO) Global Polio Eradication Initiative (GPEI) employs disease surveillance and vaccination campaigns coordinated through the WHO Regional Office for Africa (AFRO) Geographic Information System (GIS) Centre. Established in 2017, the AFRO GIS Centre played a key role in the eradication of wild-type polioviruses (WPVs) in 2020, but the COVID-19 pandemic, emergence of circulating vaccine-derived polioviruses, and transmission of WPV1 from Central Asia have led to a resurgence of polio in Sub-Saharan Africa. The AFRO GIS comprises a set of mobile device or cloud-based tools for geospatial data collection, analysis, and visualization. Using tools such as Auto-Visual Acute Flaccid Paralysis Detection and Reporting, electronic surveillance, and Integrated Supportive Supervision, GIS personnel collect polio case numbers and locations, track field worker activities, follow the movements of nomadic populations vulnerable to polio and other diseases, and determine needs for further healthcare deployments. The system is location specific and operates in real time, enabling the AFRO GIS to promptly target its responses to polio, COVID-19, Ebola virus disease, and other public health crises and natural disasters. The present review describes the components of the AFRO GIS and how the AFRO GIS Centre coordinated on-the-ground polio eradication efforts to help secure Africa's certification as WPV free. It also examines current and prospective challenges regarding other disease outbreaks in the COVID-19 era and how the AFRO GIS Centre is addressing these ongoing public health needs., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 Kipterer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Pathogens of the enterovirus genus, including poliovirus and coxsackieviruses, typically circulate in the summer months suggesting a possible positive association between warmer weather and transmission. Here we evaluate the environmental and demographic drivers of enterovirus transmission, as well as the implications of climate change for future enterovirus circulation. We leverage pre-vaccination era data on polio in the US as well as data on two enterovirus A serotypes in China and Japan that are known to cause hand, foot, and mouth disease. Using mechanistic modeling and statistical approaches, we find that enterovirus transmission appears positively correlated with temperature although demographic factors, particularly the timing of school semesters, remain important. We use temperature projections from Coupled Model Intercomparison Project Phase 6 (CMIP6) to simulate future outbreaks under late 21st-century climate change for Chinese provinces. We find that outbreak size increases with climate change on average, though results differ across climate models depending on the degree of wintertime warming. In the worst-case scenario, we project peak outbreaks in some locations could increase by up to 40%., (© 2024. The Author(s).)

This study introduces a fractional order model to investigate the dynamics of polio disease spread, focusing on its significance, unique results, and conclusions. We emphasize the importance of understanding polio transmission dynamics and propose a novel approach using a fractional order model with an exponential decay kernel. Through rigorous analysis, including existence and stability assessment applying the Caputo Fabrizio fractional operator, we derive key insights into the disease dynamics. Our findings reveal distinct disease-free equilibrium (DFE) and endemic equilibrium (EE) points, shedding light on the disease's stability. Furthermore, graphical representations and numerical simulations demonstrate the behavior of the disease under various parameter values, enhancing our understanding of polio transmission dynamics. In conclusion, this study offers valuable insights into the spread of polio and contributes to the broader understanding of infectious disease dynamics., (© 2024. The Author(s).)

Objective: To analyze vaccination coverage (VC) for polio in the municipalities of Vale do Paraíba in the State of São Paulo., Methods: This is an ecological and exploratory study of VC in 35 municipalities using a spatial approach; VC data were obtained from the IT Department of the Unified Health System (DATASUS), for the years 2015 and 2019, and categorized into Low (VC<95%) and ideal (≥95%). Information was obtained on gross domestic product (GDP), professional rates and number of basic health units (UBS) and maternal data such as age, marital status (MS) and education. Univariate and bivariate Moran indices were estimated for the years 2015 and 2019, and thematic maps were created for CV values., Results: The average VC values were 107.7%±27.2 in 2015, and 94.2%±27.8 in 2019 (p<0.05). In 2015 vs. 2019, there were 10 vs. 25 municipalities in the Low category. In 2015, the variables VC, number of UBS, age, education, and MS were spatially correlated, but in 2019 only maternal age and education were spatially correlated. The bivariate Moran was significant and negative for VC in 2019 with maternal education. There was an increase in municipalities with worsening VC values., Conclusions: The spatial approach identified a decrease in polio vaccination coverage in the studied region.

Background: Vaccine-associated paralytic poliomyelitis (VAPP) is a rare adverse event of oral poliovirus vaccines (OPV), particularly affecting immunodeficient individuals., Research Design and Methods: This study aimed to (1) Assess the association between OPV and VAPP using Vaccine Adverse Event Reporting System (VAERS) database (2) Outline patient characteristics and risk factors associated with the occurrence of VAPP in OPV recipients through a systematic review of case reports and case series. A disproportionality analysis was conducted using the data from VAERS, encompassing adverse events reported from 1990 till February 2023. Additionally, we conducted a systematic review of case reports and case series using PubMed, Scopus, and Embase databases., Results: The VAERS data revealed 130 VAPP reports among 1,739,903 OPV linked adverse events, with year 2010 reporting the strongest association. The systematic review of 37 studies highlighted VAPP occurrence within 2 months to 4 years post-vaccination, typically with acute flaccid paralysis. Immunodeficiency and perianal abscess emerged as major risk factors. Out of the 37 included studies, 27 showed consistent causal association of VAPP with OPV using WHO-AEFI causality assessment tool., Conclusion: The study emphasized the seriousness of VAPP and highlights its association with OPV, identifying immunodeficiency as a prominent contributor to VAPP manifestation.

In 2019, we conducted a cross-sectional study for polio virus seroprevalence in Guangdong province, China. We assessed the positivity rates of poliomyelitis NA and GMT in serum across various demographic groups, and the current findings were compared with pre-switch data from 2014. Using multistage random sampling method, four counties/districts were randomly selected per city, and within each, one general hospital and two township hospitals were chosen. Healthy individuals coming for medical checkups or vaccination were invited. A total of 1318 individual samples were collected and tested. In non-newborn population, age-dependent positivity rates ranged from 77.8% to 100% for PV1 NA and 70.3% to 98.9% for PV3 NA ( p  < .01). The lowest GMT values for both types (17.03 and 8.46) occurred in the 20 to <30 years age group, while peak GMTs for PV1 and PV3 were observed in 1 to <2 (340.14) and 0 to <1-year (168.90) age groups, respectively. GMTs for PV1 ( P  = .002) and PV3 ( P  = .007) in Eastern Guangdong were lower than those in the other three regions. Male participants showed higher GMTs than females ( P  = .016 and .033, respectively). In newborn population, both males and females showed higher PV1 NA positivity rates and GMTs compared to PV3 ( p  < .05). Post-switch PV3 NA positivity rates were higher than pre-switch rates ( p  = .016). GMTs of both PV1 and PV3 were significantly higher post-switch ( p  < .001). The positivity rates of NAs and GMTs remain high level, which play an important role in resisting poliomyelitis infection. Effect of the converted immunization program was more pronounced than that before.

Background: The Global Polio Eradication Initiative (GPEI) helped develop the standard acute flaccid paralysis surveillance (AFP) system worldwide, including, knowledge, expertise, technical assistance, and trained personnel. AFP surveillance can complement any disease surveillance system., Objective: This study outlines AFP surveillance evolution in Bangladesh, its success and challenging factors, and its potential to facilitate other health goals., Methods: This mixed-method study includes a grey literature review, survey, and key informant interviews (KIIs). We collected grey literature from online websites and paper documentation from GPEI stakeholders. Online and in-person surveys were conducted in six divisions of Bangladesh, including Dhaka, Rajshahi, Rangpur, Chittagong, Sylhet, and Khulna, to map tacit knowledge ideas, approaches, and experiences. We also conducted KIIs, and Data were then combined on focused emerging themes, including the history, challenges, and successes of AFP surveillance programme., Results: According to the grey literature review, survey, and KII, AFP surveillance successfully contributed to decreasing polio in Bangladesh. The major facilitating factors were multi-sectoral collaboration, Surveillance Immunization Medical Officer (SIMO) network activities, social environment, community-based surveillance, and promising political commitment. On the other hand, high population growth, hard-to-reach areas, people residing in risky zones, and polio transition planning were significant challenges. Bangladesh is also utilizing these polio surveillance assets for other vaccine-preventable diseases., Conclusion: As the world is so close to eradicating polio, the knowledge, and other assets of the AFP surveillance, could be used for other health programmes. In addition, its strengths can be leveraged for combating new and emerging diseases.

In the context of polio eradication efforts, accurate assessment of vaccination programme effectiveness is essential to public health planning and decision making. Such assessments are often based on zero-dose children, estimated using the number of children who did not receive the first dose of the Diphtheria-Tetanus-Pertussis containing vaccine as a proxy. Our study introduces a novel approach to directly estimate the number of children susceptible to poliovirus type 2 (PV2) and uses this approach to provide district-level estimates for South Africa of susceptible children born between 2017 and 2022. We used district-level data on annual doses of inactivated poliovirus vaccine (IPV) administered, live births, and population sizes, from 2017 through 2022. We imputed missing vaccination data, implemented flexible assumptions regarding dose distribution in the eligible population, and used estimated efficacy values for one, two, three, and four doses of IPV, to compute the number of susceptible and immune children by birth year. We validated our approach by comparing an intermediary output with zero-dose children (ZDC) estimated using data reported by WHO/UNICEF Estimates of National Immunization Coverage (WUENIC). Our results indicate high heterogeneity in susceptibility to PV2 across South Africa's 52 districts as of the end of 2022. In children under 5 years, PV2 susceptibility ranged from approximately 30 % in districts including Xhariep (31.9 %), Ekurhuleni (30.1 %), and Central Karoo (29.8 %), to less than 4 % in Sarah Baartman (1.9 %), Buffalo City (2.1 %), and eThekwini (3.2 %). Our susceptibility estimates were consistently higher than ZDC over the timeframe. We estimated that ZDC decreased nationally from 155,168 (152,737-158,523) in 2017 to 108,593 in 2021, and increased to 127,102 in 2022, a trend consistent with ZDC derived from data reported by WUENIC. While our approach provides a more comprehensive profile of PV2 susceptibility, our susceptibility and ZDC estimates generally agree in the ranking of districts according to risk., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Since the launch of the Global Polio Eradication Initiative in 1988, substantial progress has been made in the interruption of wild poliovirus (WPV) transmission worldwide: global eradication of WPV types 2 and 3 were certified in 2015 and 2019, respectively, and endemic transmission of WPV type 1 continues only in Afghanistan and Pakistan. After the synchronized global withdrawal of all serotype 2 oral poliovirus vaccines (OPVs) in 2016, widespread outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2) have occurred, which are linked to areas with low population immunity to poliovirus. Officials in Somalia have detected ongoing cVDPV2 transmission since 2017. Polio vaccination coverage and surveillance data for Somalia were reviewed to assess this persistent transmission. During January 2017-March 2024, officials in Somalia detected 39 cVDPV2 cases in 14 of 20 regions, and transmission has spread to neighboring Ethiopia and Kenya. Since January 2021, 28 supplementary immunization activities (SIAs) targeting cVDPV2 were conducted in Somalia. Some parts of the country are security-compromised and inaccessible for vaccination campaigns. Among 1,921 children with nonpolio acute flaccid paralysis, 231 (12%) had not received OPV doses through routine immunization or SIAs, 95% of whom were from the South-Central region, and 60% of whom lived in inaccessible districts. Enhancing humanitarian negotiation measures in Somalia to enable vaccination of children in security-compromised areas and strengthening campaign quality in accessible areas will help interrupt cVDPV2 transmission., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Geospatial data reporting from surveillance and immunization efforts is a key aspect of the World Health Organization (WHO) Global Polio Eradication Initiative in Africa. These activities are coordinated through the WHO Regional Office for Africa Geographic Information Systems Centre. To ensure the accuracy of field-collected data, the WHO Regional Office for Africa Geographic Information Systems Centre has developed mobile phone apps such as electronic surveillance (eSURV) and integrated supportive supervision (ISS) geospatial data collection programs. While eSURV and ISS have played a vital role in efforts to eradicate polio and control other communicable diseases in Africa, disease surveillance efforts have been hampered by incomplete and inaccurate listings of health care sites throughout the continent. To address this shortcoming, data compiled from eSURV and ISS are being used to develop, update, and validate a Health Facility master list for the WHO African region that contains comprehensive listings of the names, locations, and types of health facilities in each member state. The WHO and Ministry of Health field officers are responsible for documenting and transmitting the relevant geospatial location information regarding health facilities and traditional medicine sites using the eSURV and ISS form; this information is then used to update the Health Facility master list and is also made available to national ministries of health to update their respective health facility lists. This consolidation of health facility information into a single registry is expected to improve disease surveillance and facilitate epidemiologic research for the Global Polio Eradication Initiative, as well as aid public health efforts directed at other diseases across the African continent. This review examines active surveillance using eSURV at the district, country, and regional levels, highlighting its role in supporting polio surveillance and immunization efforts, as well as its potential to serve as a fundamental basis for broader public health initiatives and research throughout Africa., (©Marie Aimee Babona Nshuti, Kebba Touray, Ticha Johnson Muluh, Godwin Akpan Ubong, Reuben Opara Ngofa, Bello Isa Mohammed, Ishimwe Roselyne, David Oviaesu, Evans Mawa Oliver Bakata, Fiona Lau, John Kipterer, Hugh Henry W Green, Vincent Seaman, Jamal A Ahmed, Modjirom Ndoutabe. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 21.06.2024.)

Competing Interests: The authors have no funding or conflicts of interest to disclose.

In 1988, poliomyelitis (polio) was targeted for eradication. Global efforts have led to the eradication of two of the three wild poliovirus (WPV) serotypes (types 2 and 3), with only WPV type 1 (WPV1) remaining endemic, and only in Afghanistan and Pakistan. This report describes global polio immunization, surveillance activities, and poliovirus epidemiology during January 2022-December 2023, using data current as of April 10, 2024. In 2023, Afghanistan and Pakistan identified 12 total WPV1 polio cases, compared with 22 in 2022. WPV1 transmission was detected through systematic testing for poliovirus in sewage samples (environmental surveillance) in 13 provinces in Afghanistan and Pakistan, compared with seven provinces in 2022. The number of polio cases caused by circulating vaccine-derived polioviruses (cVDPVs; circulating vaccine virus strains that have reverted to neurovirulence) decreased from 881 in 2022 to 524 in 2023; cVDPV outbreaks (defined as either a cVDPV case with evidence of circulation or at least two positive environmental surveillance isolates) occurred in 32 countries in 2023, including eight that did not experience a cVDPV outbreak in 2022. Despite reductions in paralytic polio cases from 2022, cVDPV cases and WPV1 cases (in countries with endemic transmission) were more geographically widespread in 2023. Renewed efforts to vaccinate persistently missed children in countries and territories where WPV1 transmission is endemic, strengthen routine immunization programs in countries at high risk for poliovirus transmission, and provide more effective cVDPV outbreak responses are necessary to further progress toward global polio eradication., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

With continued wild poliovirus transmission in Afghanistan and Pakistan and circulating vaccine-derived poliovirus in certain countries, there exists an ongoing risk of importation of polioviruses into other countries, including those that have been polio-free for decades. Diversifying the poliovirus outbreak response toolkit is essential to account for different public health and epidemiological contexts. In this Personal View, we discuss data on intestinal and pharyngeal mucosal immunity induced by inactivated poliovirus vaccine (IPV), previous programmatic experience of poliovirus outbreak response with IPV, and outbreak response guidelines in countries that exclusively use IPV. With recent reports of poliovirus detection in polio-free countries such as the USA and the UK, it is important to assess the interplay of virus transmission dynamics, vaccine impact on preventing paralysis and virus spread, and regulatory complexities of using oral poliovirus vaccine (OPV) and IPV options for outbreak response. As the global eradication programme navigates through cessation of routine OPV use with replacement by IPV and stockpiling of novel OPVs, clarity on the impact of IPV use will be important for informed decision making by global, regional, and national policy makers., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: In July 2022, New York State (NYS) reported a case of paralytic polio in an unvaccinated young adult, and subsequent wastewater surveillance confirmed sustained local transmission of type 2 vaccine-derived poliovirus (VDPV2) in NYS with genetic linkage to the paralyzed patient., Methods: We adapted an established poliovirus transmission and oral poliovirus vaccine evolution model to characterize dynamics of poliovirus transmission in NYS, including consideration of the immunization activities performed as part of the declared state of emergency., Results: Despite sustained transmission of imported VDPV2 in NYS involving potentially thousands of individuals (depending on seasonality, population structure, and mixing assumptions) in 2022, the expected number of additional paralytic cases in years 2023 and beyond is small (less than 0.5). However, continued transmission and/or reintroduction of poliovirus into NYS and other populations remains a possible risk in communities that do not achieve and maintain high immunization coverage., Conclusions: In countries such as the United States that use only inactivated poliovirus vaccine, even with high average immunization coverage, imported polioviruses may circulate and pose a small but nonzero risk of causing paralysis in nonimmune individuals., Competing Interests: Potential conflicts of interest. All authors: no reported conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2023.)

In a health emergency, governments rely on public trust in their policy, and anticipate its compliance to protect health and save lives. Vaccine hesitancy compromises this process when an emergency involves infections. The prevailing discourse on vaccine hesitancy often describes it as a static phenomenon, ignoring its expanse and complexity, and neglecting the exploration of tools to address it. This article diverges from the conventional perspective by explaining the case of Pakistan and its communication strategy for the COVID-19 vaccine. Decades of polio vaccine hesitancy, rooted in the country's fight against terrorism, constitute its history. On the other hand, the first-ever launch of typhoid conjugate vaccine involving 35 million kids during 2019-2021 was a success. Against this backdrop, the country considered vaccine hesitancy as a dynamic phenomenon, interwoven with the social ecology and the responsiveness of the healthcare system. Its communication strategy facilitated those willing to receive the vaccine, while being responsive to the information needs of those still in the decision-making process. In the face of both hesitancy and a scarcity of vaccine doses, the country successfully inoculated nearly 70% (160 million) of its population in just over 1 year. People's perceptions about the COVID-19 vaccine also improved over time. This achievement offers valuable insights and tools for policymakers and strategists focused on the demand side of vaccine programmes. The lessons can significantly contribute to the global discourse on improving vaccine confidence and bolstering global health security., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

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., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

The measurement of the enterovirus and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in sewage water is relevant in the early detection of the introduction or disappearance of these viruses in the ecosystem. We evaluated the co-circulation of the enteroviruses and SARS-CoV-2 in 81 sewage water samples collected between September 2021 and April 2023 from different regions of north and southeast Romania, at the border with Ukraine. We used, for the molecular detection of the pathogens, the multiplex real-time polymerase chain reaction (PCR) assay produced for respiratory samples and the Respiratory 2.1 Plus panel Biofire Film array. The isolation of enteroviruses was performed on cell culture lines, in accordance with the World Health Organization (WHO) recommendations. By molecular investigations, we detected the SARS-CoV-2 in 22 (27%) samples, and the human rhinovirus/enterovirus in 64 (79%) samples. By isolation on cell culture lines, 27 samples (33,33%) were positive for non-polio enteroviruses, and no poliovirus strains were isolated, proving the maintenance of the polio-free status in Romania. In an emergency situation, the molecular detection of the pathogens in sewage water using a PCR system integrating sample preparation, amplification, detection, and analysis in 1 h could be implemented., Competing Interests: The author declares there is no conflict., (© 2024 The Author This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY-NC-ND 4.0), which permits copying and redistribution for non-commercial purposes with no derivatives, provided the original work is properly cited (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

Competing Interests: We declare no competing interests.

Background: Between 2018 and 2022, Nigeria experienced continuous transmission of circulating vaccine-derived type 2 poliovirus (cVDPV2), with 526 cases of cVDPV2 poliomyelitis detected in total and approximately 180 million doses of monovalent type 2 oral poliovirus vaccine (mOPV2) and 450 million doses of novel type 2 oral poliovirus vaccine (nOPV2) delivered in outbreak response campaigns. Inactivated poliovirus vaccine (IPV) was introduced into routine immunisation in 2015, with a second dose added in 2021. We aimed to estimate the effectiveness of nOPV2 against cVDPV2 paralysis and compare nOPV2 effectiveness with that of mOPV2 and IPV., Methods: In this retrospective case-control study, we used acute flaccid paralysis (AFP) surveillance data in Nigeria from Jan 1, 2017, to Dec 31, 2022, using age-matched, onset-matched, and location-matched cVDPV2-negative AFP cases as test-negative controls. We also did a parallel prospective study from March, 2021, using age-matched community controls from the same settlement as the cases. We included children born after May, 2016, younger than 60 months, for whom polio immunisation history (doses of OPV from campaigns and IPV) was reported. We estimated the per-dose effectiveness of nOPV2 against cVDPV2 paralysis using conditional logistic regression and compared nOPV2 effectiveness with that of mOPV2 and IPV., Findings: In the retrospective case-control study, we identified 509 cVDPV2 poliomyelitis cases in Nigeria with case verification and paralysis onset between Jan 1, 2017, and Dec 31, 2022. Of these, 82 children were excluded for not meeting inclusion criteria, and 363 (85%) of 427 eligible cases were matched to 1303 test-negative controls. Cases reported fewer OPV and IPV doses than test-negative controls (mean number of OPV doses 5·9 [SD 4·2] in cases vs 6·7 [4·3] in controls; one or more IPV doses reported in 95 [26%] of 363 cases vs 513 [39%] of 1303 controls). We found low per-dose effectiveness of nOPV2 (12%, 95% CI -2 to 25) and mOPV2 (17%, 3 to 29), but no significant difference between the two vaccines (p=0·67). The estimated effectiveness of one IPV dose was 43% (23 to 58). In the prospective study, 181 (46%) of 392 eligible cases were matched to 1557 community controls. Using community controls, we found a high effectiveness of IPV (89%, 95% CI 83 to 93, for one dose), a low per-dose effectiveness of nOPV2 (-23%, -45 to -5) and mOPV2 (1%, -23 to 20), and no significant difference between the per-dose effectiveness of nOPV2 and mOPV2 (p=0·12)., Interpretation: We found no significant difference in estimated effectiveness of the two oral vaccines, supporting the recommendation that the more genetically stable nOPV2 should be preferred in cVDPV2 outbreak response. Our findings highlight the role of IPV and the necessity of strengthening routine immunisation, the primary route through which IPV is delivered., Funding: Bill & Melinda Gates Foundation and UK Medical Research Council., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

On the 60 th anniversary of the initiation of the polio vaccination campaign in Spain, the significant milestone in achieving disease control is highlighted. There has been a shift from an incidence of over 2,000 yearly cases in the 1960s to a sustained absence of wild poliovirus (WPV) since 1988. Despite the observed negative impact on polio vaccination coverage at the onset of the COVID-19 pandemic, these rates gradually recovered, reaching 98.2% in primary vaccination in 2022. Over the past decade, two essential elements have been identified to maintain the goal of polio elimination and that reinforces the importance of sustaining high vaccination coverage: robust epidemiological surveillance systems and a swift response to alerts to protect the vulnerable population and prevent virus reintroduction. In order to achieve eradication, it is crucial to interrupt international transmission and maintain continuous high-quality surveillance and effective coordination across different levels in response to any detection of PV, wild or vaccine derived. This article aimed to provide a comprehensive view of the polio eradication situation in Spain, focusing on the key events that occurred in the last decade and the present and future challenges., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Introduction: After trivalent oral poliovirus vaccine (tOPV) cessation, Pakistan has maintained immunity to type 2 poliovirus by administering inactivated polio vaccine (IPV) in routine immunization, alongside monovalent OPV type 2 (mOPV2) and IPV in supplementary immunization activities (SIAs). This study assesses the change in poliovirus type 2 immunity after tOPV withdrawal and due to SIAs with mOPV2 and IPV among children aged 6-11 months., Methods: Three cross-sectional sequential serological surveys were conducted in 12 polio high-risk areas of Pakistan. 25 clusters from each geographical stratum were selected utilizing probability proportional to size., Results: Seroprevalence of type 2 poliovirus was 49%, with significant variation observed among surveyed areas; <30% in Pishin, >80% in Killa Abdullah, Mardan & Swabi, and Rawalpindi. SIAs with IPV improved immunity from 38 to 57% in Karachi and 60 to 88% in Khyber. SIAs with IPV following mOPV2 improved immunity from 62 to 65% in Killa Abdullah, and combined mOPV2 and IPV SIAs in Pishin improved immunity from 28 to 89%. Results also reflected that immunity rates for serotypes 1 and 3 were consistently above 90% during all three phases and across all geographical areas., Conclusion: The study findings highlight the importance of implementing effective vaccination strategies to prevent the re-emergence of poliovirus. Moreover, the results provide crucial information for policymakers working toward achieving global polio eradication., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hussain, Umer, Khan, Sajid, Ahmed, Begum, Iqbal, Alam, Safdar, Baig, Voorman, Partridge and Soofi.)

Background: Novel oral poliovirus vaccine type 2 (nOPV2) has been engineered to improve the genetic stability of Sabin oral poliovirus vaccine (OPV) and reduce the emergence of circulating vaccine-derived polioviruses. This trial aimed to provide key safety and immunogenicity data required for nOPV2 licensure and WHO prequalification., Methods: This phase 3 trial recruited infants aged 18 to <52 weeks and young children aged 1 to <5 years in The Gambia. Infants randomly assigned to receive one or two doses of one of three lots of nOPV2 or one lot of bivalent OPV (bOPV). Young children were randomised to receive two doses of nOPV2 lot 1 or bOPV. The primary immunogenicity objective was to assess lot-to-lot equivalence of the three nOPV2 lots based on one-dose type 2 poliovirus neutralising antibody seroconversion rates in infants. Equivalence was declared if the 95% CI for the three pairwise rate differences was within the -10% to 10% equivalence margin. Tolerability and safety were assessed based on the rates of solicited adverse events to 7 days, unsolicited adverse events to 28 days, and serious adverse events to 3 months post-dose. Stool poliovirus excretion was examined. The trial was registered as PACTR202010705577776 and is completed., Findings: Between February and October, 2021, 2345 infants and 600 young children were vaccinated. 2272 (96·9%) were eligible for inclusion in the post-dose one per-protocol population. Seroconversion rates ranged from 48·9% to 49·2% across the three lots. The minimum lower bound of the 95% CIs for the pairwise differences in seroconversion rates between lots was -5·8%. The maximum upper bound was 5·4%. Equivalence was therefore shown. Of those seronegative at baseline, 143 (85·6%) of 167 (95% CI 79·4-90·6) infants and 54 (83·1%) of 65 (71·7-91·2) young children seroconverted over the two-dose nOPV2 schedule. The post-two-dose seroprotection rates, including participants who were both seronegative and seropositive at baseline, were 604 (92·9%) of 650 (95% CI 90·7-94·8) in infants and 276 (95·5%) of 289 (92·4-97·6) in young children. No safety concerns were identified. 7 days post-dose one, 78 (41·7%) of 187 (95% CI 34·6-49·1) infants were excreting the type 2 poliovirus., Interpretation: nOPV2 was immunogenic and safe in infants and young children in The Gambia. The data support the licensure and WHO prequalification of nOPV2., Funding: Bill & Melinda Gates Foundation., Competing Interests: Declaration of interests ET works for PT Biofarma who manufacture the novel oral poliovirus vaccine type 2 and the bivalent oral poliovirus vaccine used in this trial. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: The outbreaks of circulating Vaccine Derived Polio Viruses (cVDPVs) have emerged as a major challenge for the final stage of polio eradication. In Yemen, an explosive outbreak of cVDPV2 was reported from August 2021 to December 2022. This study aims to compare the patterns of cVDPV2 outbreak, response measures taken by health authorities, and impacts in southern and northern governorates., Method: A retrospective descriptive study of confirmed cases of VDPV2 was performed. The data related to cVDPV2 as well as stool specimens and environmental samples that were shipped to WHO-accredited labs were collected by staff of surveillance. Frequencies and percentages were used to characterize and compare the confirmed cases from the southern and northern governorates. The average delayed time as a difference in days between the date of sample collection and lab confirmation was calculated., Results: The cVDPV2 was isolated from 227 AFP cases reported from 19/23 Yemeni governorates and from 83% (39/47) of environmental samples with an average of 7 months delayed from sample collection. However, the non-polio AFP (NPAFP) and adequate stool specimen rates in the north were 6.7 and 87% compared to 6.4 and 87% in the south, 86% (195) and 14%(32) out of the total 227 confirmed cases were detected from northern and southern governorates, respectively. The first and second cases of genetically linked isolates experienced paralysis onset on 30 August and 1st September 2021. They respectively were from Taiz and Marib governorates ruled by southern authorities that started vaccination campaigns as a response in February 2022. Thus, in contrast to 2021, the detected cases in 2022 from the total cases detected in the south were lower accounting for 22% (7 of 32) of compared to 79% (155 of 195) of the total cases the north., Conclusion: A new emerging cVDPV2 was confirmed in Yemen. The result of this study highlighted the impact of vaccination campaigns in containing the cVDPV2 outbreak. Maintaining a high level of immunization coverage and switching to nOPV2 instead of tOPV and mOPV2 in campaigns are recommended and environmental surveillance should be expanded in such a risky country., (© 2024. The Author(s).)

Background: Novel oral poliovirus vaccine (OPV) type 2 (nOPV2) has been made available for outbreak response under an emergency use listing authorization based on supportive clinical trial data. Since 2021 more than 350 million doses of nOPV2 were used for control of a large outbreak of circulating vaccine-derived poliovirus type 2 (cVDPV2) in Nigeria., Methods: Using a bayesian time-series susceptible-infectious-recovered model, we evaluate the field effectiveness of nOPV2 immunization campaigns in Nigeria compared with campaigns using monovalent OPV type 2 (mOPV2)., Results: We found that both nOPV2 and mOPV2 campaigns were highly effective in reducing transmission of cVDPV2, on average reducing the susceptible population by 42% (95% confidence interval, 28-54%) and 38% (20-51%) per campaign, respectively, which were indistinguishable from each other in this analysis (relative effect, 1.1 [.7-1.9]). Impact was found to vary across areas and between immunization campaigns., Conclusions: These results are consistent with the comparable individual immunogenicity of nOPV2 and mOPV2 found in clinical trials but also suggest that outbreak response campaigns may have small impacts in some areas requiring more campaigns than are suggested in current outbreak response procedures., Competing Interests: Potential conflicts of interest. A. V., H. L., A. S. B., and S. O. are employed by the Bill & Melinda Gates Foundation. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

In 1994, the World Health Organization Region of the Americas was declared polio-free. In July 2022, a confirmed case of paralytic polio in an unvaccinated adult resident of Rockland County, New York was reported by the New York State Department of Health (NYSDOH) and Rockland County Department of Health (RCDOH). While only one case was identified, a single case of paralytic polio represents a public health emergency in the United States. The patient's county of residence was identified to have low vaccination coverage indicating that the community was at risk for additional cases. Disease outbreaks are resource-intensive and incur high costs to the patient, local health departments, and to society. These costs are potentially avoidable for vaccine-preventable diseases and thus, highlight the urgency to not only interrupt transmission but to prevent future vaccine-preventable disease outbreaks by improving vaccination coverage. Following case confirmation, an investigation and response was initiated by NYSDOH, along with local health departments and the Centers for Disease Control and Prevention (CDC). After the initial investigation and response, collaborative efforts to mitigate risk and strengthen routine immunization continued, which included provider outreach and immunization record assessments of Head Start and licensed childcare facilities (primarily those with missing or incomplete required vaccination coverage reports from the previous year) in Rockland County. We estimated the costs of (1) provider outreach and (2) childcare and pre-kindergarten immunization record assessments of select licensed childcare and Head Start facilities in Rockland County. The total labor cost incurred for these activities was $138,514 with a total of 2,555 h incurred. Often there are unique opportunities in the midst of an outbreak for public health to implement activities to proactively address low vaccination and strengthen vaccination coverage and possibly prevent future outbreaks. Understanding the cost of these activities might help inform future outbreak planning., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Background: Acute Flaccid Paralysis (AFP) surveillance is the gold standard in the polio eradication initiative. The environmental component of polio surveillance can detect circulating Polioviruses from sewage without relying on clinical presentation. The effectiveness of the Environmental Surveillance (ES) is crucial to global polio eradication. We assessed the usefulness and attributes of the ES system in the Northern region and determined if the system is meeting its objectives., Methods: We conducted a descriptive cross-sectional evaluation in the Northern region from 2019 to 2020 using the updated US Centers for Disease Control and Prevention guideline. We interviewed stakeholders, reviewed records, and observed surveillance activities from 29th March to 7th May, 2021. Quantitative data were analyzed manually as frequencies and proportions whiles thematic analysis was used for the qualitative data., Results: One of 48 (2.1%) samples collected tested positive for circulating vaccine-derived Poliovirus (cVDPV). The cVDPV detection triggered enhanced AFP surveillance that resulted in the identification of a case of AFP. Three rounds of polio vaccination campaigns were organized. All surveillance officers interviewed were willing to continue providing their services for the ES. Reporting form has few variables and is easy to complete. The completeness of forms was 97.9% (47/48). Samples collected were dispatched on the same day to the testing laboratory. The system's data was managed manually., Conclusion: The system was useful in detecting polio outbreaks. Data quality was good, the system was simple, flexible, acceptable, representative, and fairly stable. Sensitivity was high but predictive value positive was low. Timeliness in reporting was good but feedback from the national level could not be assessed. There is a need to improve on the feedback system and ensure that, the surveillance data is managed electronically., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Baguune et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: Poliovirus (PV) and non-polio enteroviruses (NPEV) belong to the Picornaviridae family. They are found worldwide and are responsible for a wide range of diseases such as acute flaccid paralysis (AFP). This study aimed to evaluate the detection rate of PV and NPEV in stool samples from children under fifteen years of age presenting with AFP in Cameroon and their distribution over time., Methodology: Stool samples were collected as part of poliovirus surveillance throughout Cameroon from 2015 to 2020. Virus isolation was performed using RD and L20B cells maintained in culture. Molecular methods such as intratypic differentiation were used to identify PVs serotypes and analysis of the VP1 genome was performed., Results: A total of 12,354 stool samples were analyzed. The EV detection rate by virus isolation was 11.42% (1411/12354). This rate varied from year to year with a mean distribution of 11.41 with a 95% confidence interval [11.37; 11.44]. Of the viruses detected, suspected poliovirus accounted for 31.3% (442/1411) and NPEV 68.67% (969/1411). No wild poliovirus (WPV) was isolated. Sabin types 1 and 3 were continuously isolated. Surprisingly, from February 2020, vaccine-derived PV type 2 (VDPV2) was detected in 19% of cases, indicating its resurgence., Conclusions: This study strongly supports the successful elimination of WPV in Cameroon and the resurgence of VDPV2. However, as long as VDPV outbreaks continue to be detected in Africa, it remains essential to monitor how they spread., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2024 Daniel K Njile, Serge A Sadeuh-Mba, Michel Tabonfack Atemkeng, Anicet Ahanda, Jean Blaise Momo, Raissa Pekekue Nforifum, Ernestine Etéré, Marie Claire Endegue-Zanga, Onana Boyomo, Marlise D Djoumetio, Jude Anfumbom Kfutwah, Ousmane M Diop, Richard Njouom.)

The presence of epidemic outbreaks of poliomyelitis in the initial and central decades of the last century constituted an important Public Health problem due to the absence of effective treatments because it preferentially affected children, in environments with acceptable levels of health, and the fear of the paralytic sequelae. This work attempted to reconstruct some of the responses that were given in the Spanish state, both in professional health settings and from alternative heterodox approaches such as the Kenny method, taking as a reference axis the compassionate culture that was behind the development of the measures. adopted and their critical analysis, in the period before the implementation of anti-polio vaccines., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Introduction: Borno state in north-eastern Nigeria is the epicentre of the >10 years' insurgency activities that have affected the region since 2009, resulting in the destruction of health facilities, killing of health workers, massive population displacement and lack of access to populations to provide health services. This article demonstrates how the involvement of community informants from insecure areas (CIIA) to conduct polio surveillance in security-challenged settlements of Borno state contributed to the expansion of polio surveillance reach beyond polio vaccination reach., Method: In each of the 19 security compromised Local Government areas (LGAs) with community informants from insecure areas, Android phones enabled with Vaccination Tracking System (VTS) technology and Open Data Kit (ODK) mobile application were provided to capture geo-coordinates as evidence (geo evidence) for polio surveillance activity conducted. These geo evidence captured were uploaded and mapped to show insecure settlements reached with polio surveillance and those yet to be reached., Results: A total of 3183 security compromised settlements were reached for polio surveillance between March 2018 and October 2019 with valid geo evidence, 542 of these security-compromised settlements had not been previously reached by any other intervention for polio surveillance or polio vaccination., Conclusion: The capturing of geo-coordinates as a proxy indicator of polio surveillance activity conducted by informants provided significant evidence of settlements reached for sustained polio surveillance even when a case of Acute Flaccid Paralysis (AFP) had not been reported from these settlements. Using the geo evidence captured by CIIA in insecure settlements, we have demonstrated the expansion of polio surveillance reach beyond polio vaccination reach in Borno state., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In May 2016, the Global Polio Eradication Initiative (GPEI) coordinated the cessation of all use of type 2 oral poliovirus vaccine (OPV2), except for emergency outbreak response. Since then, paralytic polio cases caused by type 2 vaccine-derived polioviruses now exceed 3,000 cases reported by 39 countries. In 2022 (as of April 25, 2023), 20 countries reported detection of cases and nine other countries reported environmental surveillance detection, but no reported cases. Recent development of a genetically modified novel type 2 OPV (nOPV2) may help curb the generation of neurovirulent vaccine-derived strains; its use since 2021 under Emergency Use Listing is limited to outbreak response activities. Prior modeling studies showed that the expected trajectory for global type 2 viruses does not appear headed toward eradication, even with the best possible properties of nOPV2 assuming current outbreak response performance. Continued persistence of type 2 poliovirus transmission exposes the world to the risks of potentially high-consequence events such as the importation of virus into high-transmission areas of India or Bangladesh. Building on prior polio endgame modeling and assuming current national and GPEI outbreak response performance, we show no probability of successfully eradicating type 2 polioviruses in the near term regardless of vaccine choice. We also demonstrate the possible worst-case scenarios could result in rapid expansion of paralytic cases and preclude the goal of permanently ending all cases of poliomyelitis in the foreseeable future. Avoiding such catastrophic scenarios will depend on the development of strategies that raise population immunity to type 2 polioviruses., (© 2023 Society for Risk Analysis.)

Due to the very low, but nonzero, paralysis risks associated with the use of oral poliovirus vaccine (OPV), eradicating poliomyelitis requires ending all OPV use globally. The Global Polio Eradication Initiative (GPEI) coordinated cessation of Sabin type 2 OPV (OPV2 cessation) in 2016, except for emergency outbreak response. However, as of early 2023, plans for cessation of bivalent OPV (bOPV, containing types 1 and 3 OPV) remain undefined, and OPV2 use for outbreak response continues due to ongoing transmission of type 2 polioviruses and reported type 2 cases. Recent development and use of a genetically stabilized novel type 2 OPV (nOPV2) leads to additional potential vaccine options and increasing complexity in strategies for the polio endgame. Prior applications of integrated global risk, economic, and poliovirus transmission modeling consistent with GPEI strategic plans that preceded OPV2 cessation explored OPV cessation dynamics and the evaluation of options to support globally coordinated risk management efforts. The 2022-2026 GPEI strategic plan highlighted the need for early bOPV cessation planning. We review the published modeling and explore bOPV cessation immunization options as of 2022, assuming that the GPEI partners will not support restart of the use of any OPV type in routine immunization after a globally coordinated cessation of such use. We model the potential consequences of globally coordinating bOPV cessation in 2027, as anticipated in the 2022-2026 GPEI strategic plan. We do not find any options for bOPV cessation likely to succeed without a strategy of bOPV intensification to increase population immunity prior to cessation., (© 2023 Society for Risk Analysis. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Introduction: the Africa region was certified indigenous wild poliovirus-free in August 2020. Countries in East and Southern Africa have, during acute flaccid paralysis (AFP) and environmental surveillance (ES), detected equally concerning vaccine-derived polioviruses (VDPVs) that have not been systematically documented to guide programming in the sub-region. The study documents trends and salient observations of the VDPVs by country of detection, for 11 years from 2010 to 2021., Methods: we conducted secondary data analysis, a descriptive study design, by deploying field and laboratory of AFP and environmental surveillance databases of the 20 East and Southern African countries from 2010 to 2021., Results: a total of 318 VDPVs were reported over the study period. The majority were from AFP cases (58.8%) and the rest equally distributed between healthy community children and environmental surveillance sources. More polioviruses were detected after 2016 than during the period before. We observed that more boys were affected by VDPVs compared to girls. Children under 5 years were more affected than other age groups, with a mean age of 3.6 years. Delay of samples in the field seemed to increase the likelihood of not reporting VDPVs and not mounting timely public health detailed investigations and vaccination responses., Conclusion: the study provides useful evolutional trends of VDPVs for surveillance and vaccination programming. We also noted that the VDPV2s have been increasing after the 2016 tOPV to oral polio vaccine (bOPV) switch. The COVID-19 pandemic emergence in 2020, led to a decline in AFP, ES surveillance, and immunization activities. Our findings point to the need to implement enhanced tailored childhood immunization recovery strategies and to speed up the use of inactivated polio vaccine (IPV) to boost population immunity., Competing Interests: The authors declare no competing interests., (Copyright: Charles Byabamazima et al.)

Background: The current polio epidemiology in Pakistan poses a unique challenge for global eradication as the country is affected by ongoing endemic poliovirus transmission. Across the country, 40 union councils (UCs) which serve as core reservoirs for poliovirus with continuous incidences of polio cases are categorized as super-high-risk union councils (SHRUCs)., Methodology: A cross-sectional survey was conducted in 39 SHRUCs using a two-stage stratified cluster sampling technique. 6,976 children aged 12-23 months were covered. A structured questionnaire was used for data collection. Data were analyzed using STATA version 17., Results: Based on both vaccination records and recall, 48.3% of children were fully-, 35.4 % were partially-, and 16.3% were non-vaccinated in the SHRUC districts. A child is considered fully vaccinated when h/she completed vaccination for BCG, OPV0, OPV 1-3, Penta 1-3, PCV 1-3, IPV, and MCV1. Vaccination cards were seen for over half of the children in the SHRUC districts of Khyber Pakhtunkhwa (KP) and the majority of the SHRUC districts in Sindh, except for the SHRUC district of Malir the districts of Balochistan. Results for polio vacancies show that 60.9% of children from the SHRUC districts were vaccinated with at least three doses of OPV and one dose of IPV, while 20.4% were vaccinated with any OPV doses or IPV and 18.7% of children did not receive any polio vaccines. The dropout rate between vaccine visits was higher than the WHO-recommended cutoff point of 10% for all vaccine doses in the SHRUC districts. The likelihood of being fully vaccinated was higher among the children of educated parents. Full vaccination was found significant among the children of any SHRUC districts compared to district Killa Abdullah., Conclusion: Context-specific strategies with more focus on community engagement and targeted mobilization, along with robust monitoring mechanisms, would help address the underlying challenges of under-immunization in the SHRUCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: During 2020 and immediately prior to the COVID-19 pandemic, Sudan was experiencing multiple emergencies including violence, seasonal flooding, and vector-borne disease outbreaks. After more than ten years since its last case of wild poliovirus, Sudan declared a circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreak on 9 August 2020., Methods: cVDPV2 outbreak response data and programme documents of the Federal Ministry of Health and WHO were reviewed. Surveillance data was verified through WHO-recommended procedures for detecting and characterizing polioviruses from stool and sewage samples collected from acute flaccid paralysis (AFP) cases and the environment., Results: This outbreak in Sudan led to a total of 58 confirmed cases of cVDPV2 from 15 of the 18 states. Two nationwide vaccination campaigns were held to increase immunity of children under-five against poliovirus type 2. Funding challenges were overcome by intense additional resource mobilization from in-country sources. The funding gap was bridged from domestic resources (49%) sourced through GPEI partners, and in-country humanitarian funding mechanisms., Conclusions: During an outbreak response and challenge of funding shortfall, mobilizing in-country resources is possible through coordinated approaches, regular communication with partners, disaggregation of needs, and matching in-kind and financial support to fill gaps. A cVDPV2 outbreak requires a fast, resourced, and quality response to stop virus circulation., (© 2023. The Author(s).)

More than 100 types of non-polio enteroviruses (NPEVs) are ubiquitous in the human population and cause a variety of symptoms ranging from very mild to meningitis and acute flaccid paralysis (AFP). Much of the information regarding diverse pathogenic properties of NPEVs comes from the surveillance of poliovirus, which also yields NPEV. The analysis of 265 NPEV isolations from 10,433 AFP cases over 24 years of surveillance and more than 2500 NPEV findings in patients without severe neurological lesions suggests that types EV-A71, E13, and E25 were significantly associated with AFP. EV-A71 was also significantly more common among AFP patients who had fever at the onset and residual paralysis compared to all AFP cases. In addition, a significant disparity was noticed between types that were common in humans (CV-A2, CVA9, EV-A71, E9, and E30) or in sewage (CVA7, E3, E7, E11, E12, and E19). Therefore, there is significant evidence of non-polio viruses being implicated in severe neurological lesions, but further multicenter studies using uniform methodology are needed for a definitive conclusion.

Background: A Meningitis and Encephalitis Surveillance (MERIN) was implemented in 2003 in Lower Saxony, Germany as an alternative to acute flaccid paralyses surveillance, as the latter did not reach WHO sensitivity criteria. The system provides information on circulating enterovirus (EV) serotypes by focussing on patients with suspected aseptic meningitis, encephalitis or acute flaccid paralysis and contributes to the national surveillance in documenting polio free status. MERIN is based on voluntary participation of hospitals. Therefore, our evaluation focusses on acceptability of the system's objectives and performance, and identifying areas for improvement., Methods: To assess acceptability, 32 contributing hospitals were invited to an online-based survey (11/2021 to 01/2022) to rate the MERIN objectives, laboratory's performance, their workload, modes of processes and communication. Ideas for improvement were collected in open fields. In addition, data completeness and timeliness of laboratory diagnostics were assessed., Results: Of 32 hospitals, 21 responded (66% response rate), sending 30 questionnaires, 25 from pediatric and 5 from neurological departments. High levels of satisfaction with the communication (≥ 96%), timeliness (≥ 81%), and distribution of the results (≥ 85%) were reported, 97% of participants judged the required workload as adequate. The median proportion of eligible patients included in MERIN was 75%. Participants gave rapid and reliable diagnostic testing the highest priority (96%), while monitoring of Germany's polio-free status was rated the lowest (61%). Providing medical reports digitally as well as regular updates about circulating EV serotypes were identified as areas for improvement. Data completeness of selected variables ranged from 78.3 to 99.9%. Median time between sample collection and arrival at laboratory was 2 days [IQR 1-3], EV diagnostics via PCR took one day [IQR 0-6] and EV isolation on cell culture 11 days [IQR 10-13]., Conclusion: MERIN is a highly accepted surveillance system. Its quality was enhanced further by addressing the suggested improvements such as regular reports on circulating EV serotypes and facilitating digital access to laboratory results. Our results emphasise the importance of recognizing and considering participants' motivations and expectations, and addressing their priorities, even if this is not the surveillance system's main focus. This approach can be applied to surveillance systems of other non-mandatory notifiable diseases., (© 2024. The Author(s).)

Background: New York State (NYS) reported a polio case (June 2022) and outbreak of imported type 2 circulating vaccine-derived poliovirus (cVDPV2) (last positive wastewater detection in February 2023), for which uncertainty remains about potential ongoing undetected transmission., Research Design and Methods: Extending a prior deterministic model, we apply an established stochastic modeling approach to characterize the confidence about no circulation (CNC) of cVDPV2 as a function of time since the last detected signal of transmission (i.e. poliovirus positive acute flaccid myelitis case or wastewater sample)., Results: With the surveillance coverage for the NYS population majority and its focus on outbreak counties, modeling suggests a high CNC (95%) within 3-10 months of the last positive surveillance signal, depending on surveillance sensitivity and population mixing patterns. Uncertainty about surveillance sensitivity implies longer durations required to achieve higher CNC., Conclusions: In populations that maintain high overall immunization coverage with inactivated poliovirus vaccine (IPV), rare polio cases may occur in un(der)-vaccinated individuals. Modeling demonstrates the unlikeliness of type 2 outbreaks reestablishing endemic transmission or resulting in large absolute numbers of paralytic cases. Achieving and maintaining high immunization coverage with IPV remains the most effective measure to prevent outbreaks and shorten the duration of imported poliovirus transmission.

Background: Despite multiple revisions of targets and timelines in polio eradication plans since 1988, including changes in supplemental immunization activities (SIAs) that increase immunity above routine immunization (RI) coverage, poliovirus transmission continues as of 2024., Methods: We reviewed polio eradication plans and Global Polio Eradication Initiative (GPEI) annual reports and budgets to characterize key phases of polio eradication, the evolution of poliovirus vaccines, and the role of SIAs. We used polio epidemiology to provide context for successes and failures and updated prior modeling to show the contribution of SIAs in achieving and maintaining low polio incidence compared to expected incidence for the counterfactual of RI only., Results: We identified multiple phases of polio eradication that included shifts in targets and timelines and the introduction of different poliovirus vaccines, which influenced polio epidemiology. Notable shifts occurred in GPEI investments in SIAs since 2001, particularly since 2016. Modeling results suggest that SIAs play(ed) a key role in increasing (and maintaining) high population immunity to levels required to eradicate poliovirus transmission globally., Conclusions: Shifts in polio eradication strategy and poliovirus vaccine usage in SIAs provide important context for understanding polio epidemiology, delayed achievement of polio eradication milestones, and complexity of the polio endgame.