Search Results (68)

Background: This study aimed to analyze the patterns and underlying reasons associated with population movement across Sindh, Pakistan. Methods: Cross-sectional surveys were conducted in response to the detection of WPV1 in various districts in Sindh province, where genetic linkages with poliovirus isolates in Karachi had been identified. The surveys targeted union councils (UCs) contributing sewage to the environmental sample collection sites where WPV1 was detected. Results: In the Karachi division a total of 1392 participants were interviewed, and outside Karachi 1471 participants were included. A significantly higher proportion of female participants were interviewed in Karachi (n = 72, 55.0%) compared to other divisions of Sindh (n = 794, 45.0%) (p < 0.001). Linguistic distribution varied significantly between regions, with Pashto speakers predominating in Karachi (n = 336, 86.4%), and Sindhi in other divisions (n = 501, 79.4%) (p < 0.001). OPV coverage exceeded 90% across all districts, and over 85% of children received RI vaccines. Travel patterns also differed significantly; participants from Karachi (n = 686, 44.2%) were less likely to report travel compared to other divisions (n = 865, 55.8%), who frequently traveled for family events, business, or employment (p < 0.001). Conclusions: It is critical to redefine high-risk populations annually based on updated mobility data, social survey analyses, and virus detection via surveillance to better identify and reach unvaccinated children in the Pakistan polio program. In addition, strategically placed PTPs along both formal and informal travel corridors based on an updated risk framework will enhance vaccination, thereby reducing the risk of virus spread. Full article

As part of the WHO’s Global Polio Eradication Initiative, acute flaccid paralysis (AFP) surveillance in children under 15 years old is crucial for monitoring the emergence of polioviruses and tracking Non-Polio Enteroviruses (NPEVs). This study outlines the past 17 years of AFP surveillance in Greece from 2008 to 2024, during which a total of 256 AFP cases were recorded. Stool samples from these cases were analyzed using virus isolation in cell cultures (RD/L20B) and sequencing of NPEV-positive samples. The Attica region reported the highest number of cases with 81 (31%), followed by Central Macedonia and Crete, each with 29 cases (11%). The overall analysis of fecal specimens identified the etiological agent in 18 (7%) specimens, with 13 (4.7%) classified as NPEVs, 4 (1.5%) as adenoviruses, and 1 (0.4%) as a parechovirus. Coxsackievirus A, Coxsackievirus B, and various Echoviruses were the most frequently detected NPEV types. Notably, more than half of these positive specimens (10/18) were from the Attica region, which has the highest population density. These findings highlight the ongoing relevance of AFP surveillance in polio-free settings for broader pathogen monitoring and public health preparedness. Continued vigilance and investment in AFP surveillance are critical to sustaining Greece’s polio-free status and detecting emerging viral threats. Full article

Background: Pakistan reported its first case of COVID-19 in February 2020 and joined other countries in activating a national emergency response following the declaration of the COVID-19 pandemic by the World Health Organization (WHO). Playing a vital role in the early phase of the country’s response was the National Stop Transmission of Polio (NSTOP) program, a highly trained cadre of polio workers who ordinarily support polio eradication efforts in the country. Methods: We developed a reporting tool using Microsoft Excel that tracked the activities of NSTOP officers to support the COVID-19 response. All NSTOP officers submitted their activity reports fortnightly using this reporting tool. Each provincial NSTOP officer reviewed and compiled their respective officers’ reports and sent them to the federal NSTOP Team. We present a summary of the reports for the period from 1 March 2020 to 31 July 2020. Results: A total of 71 officers of the NSTOP program supported various aspects of Pakistan’s COVID-19 response, including coordination, detection and response activities, surveillance, quarantine/isolation management, training and orientation sessions for healthcare personnel, data analysis, community engagement, and risk communication. They successfully investigated 32,729 suspected COVID-19 cases, of which about one-third were confirmed cases, and facilitated the collection and dispatch of >57,000 samples from these cases. Conclusions: This report details NSTOP contributions to the early phase of the COVID-19 response in Pakistan, demonstrating the value of polio investments beyond eradicating the disease to encompass having a workforce that is ready to respond to emergent disease threats and outbreaks. Such a workforce could also play a role in strengthening the capacity of existing immunization systems to help improve routine vaccination coverage in resource-limited settings. Full article

Introduction: Polio supplementary immunisation activities (SIA) are implemented to rapidly increase vaccination coverage and interrupt the transmission of poliovirus in a specified geographical area. Polio SIA complements routine immunisation and is crucial for the eradication of the disease by increasing population immunity. However, several contextual factors (i.e., implementation determinants) can influence the success or failure of polio SIA implementation; as such, understanding their dynamics can enhance proactive planning for practice improvement. This study aimed to explore and map the contextual factors of polio SIA implementation in the African region using a critical systems thinking approach. Methods: A rapid review of published and grey literature was conducted. The search included the Global Polio Eradication Initiative library for programmatic reports and two databases (PubMed and Google Scholar). Data extraction was performed using a structured tool. Thematic analysis was performed to categorise the identified contextual factors according to the domains and constructs of the Consolidated Framework for Implementation Research (CFIR). Then, a causal loop diagram (CLD) was used to map the linkages between the identified factors. Results: A total of seventy-eight contextual factors across the five CFIR domains were identified: three for innovation, twenty for outer setting, sixteen for inner setting, twenty-six for individuals, and thirteen for the implementation process. A system map of all the factors using CLD revealed multiple contingent connections, with eleven reinforcing loops and four balancing loops. Conclusions: This study identified the multilevel nature of the contextual factors that influence polio SIA, including their dynamics. The integration of CLD and CFIR in this study offers critical insights into the potential feedback loops that exists between the contextual factors which can be used as leverage points for policy and practice improvements, including tailoring strategies to enhance polio campaign implementation effectiveness, especially with the expanded use of the novel Oral Polio Vaccine type 2 (nOPV2) across countries in the region. Full article

The eradication of poliovirus remains a global health priority, with inactivated polio vaccines (IPVs) playing a pivotal role in immunization strategies. Over the past decades, advancements in IPV production have focused on optimizing safety, efficacy, and immunogenicity while addressing vaccine production and logistical challenges. This paper discusses a novel IPV candidate, ultraIPV^TM, which departs from conventional formalin inactivation and uses a modern ultraviolet C (UVC) inactivation technology that includes a powerful antioxidant that protects virus epitopes from damage during and after irradiation. The potential of UVC inactivation to maintain structural integrity and immunogenicity of viral antigens, while circumventing safety issues with conventional vaccines, could bolster global polio eradication efforts and holds promise for applications to numerous other viral pathogens. Wistar rats were immunized with three dosages of ultraIPV^TM, IPOL^R, or vehicle alone. Immune responses were analyzed by whole-virus ELISA and antiviral neutralizing responses. Toxicity was analyzed primarily by increases in body weight and cytokine ELISA. Tolerability was analyzed by gross pathological and histological examinations. ultraIPV^TM was determined to be immunogenic and non-toxic. No pathological or histological abnormalities related to the vaccine were observed. The data suggest that ultraIPV^TM is immunogenic and well-tolerated in rats. Full article

Background: Poliomyelitis is a vaccine-preventable disease, with oral poliomyelitis vaccines (OPVs) and injectable poliomyelitis vaccines. In the Democratic Republic of the Congo (DRC), circulating vaccine-derived polioviruses (VDPVs) persist due to intrinsic and extrinsic factors, including the quality of the cold chain, which may make the vaccines less effective. This study’s objective was to evaluate the cold chain’s quality of OPVs and its effect on the vaccine’s viability and potency at different levels in health systems in Kinshasa. Methods: A cross-sectional study was conducted in Kinshasa, collecting OPVs at different levels of the health pyramid. Vaccine viability was assessed by cell culture using a modified World Health Organization (WHO) protocol, and the viral titer was determined using the Karber formula. The vaccine titer was classified as “very good”, “good”, or “poor” according to the WHO standard’s viral titer. Results: A total of 53 vaccines were collected and analyzed, compressing 38 bivalent oral poliomyelitis (bOPV) vaccines and 15 novel oral poliomyelitis vaccines, type 2 (nOPV2). The viral titer ranged from log10^5.8 to log 10^7.3 and from log10^5.4 to log10^8.9 for the nOPV2 and the bOPV, respectively. Of these 53 vaccine samples, 10% of the bOPVs showed viral titers below the recommended WHO threshold (>10⁶ CCID₅₀/dose), 100% of the nOPV2 had viral titers within the WHO standards (>10⁵ CCID₅₀/dose), and a significant decline in the viral titer was observed for both types of vaccines (nOPV2 and bOPV) as the distribution progressed along the level of the health pyramid. Conclusions: This study demonstrated that the viral titer of OPV declined from central to peripheral areas in routine and campaign strategies in Kinshasa. Full article

Background: Polio is an infectious viral disease that can cause paralytic complications and death. Despite global efforts to eradicate wild poliovirus, there are ongoing outbreaks globally and the mutated form of paralytic polio, i.e., circulating vaccine-derived poliovirus, is present in Nigeria. Low vaccination uptake and poor sanitation are responsible for outbreaks in countries where polio had previously been eliminated. This review identifies policies, strategies and interventions for polio eradication and assesses their impact on polio vaccine uptake and eradication efforts in Nigeria. Methods: A systematic literature review was conducted and guided by the Population, Intervention, Comparator and Outcome (PICO) framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart, with identified articles appraised using the Critical Appraisal Skills Program appraisal tool. Results: A total of 393 articles were identified, of which 26 articles were included. Key findings indicate polio intervention services, policies and mass campaigns have had a significant impact on eradicating WPV in Nigeria. However, there are gaps in variant polio eradication efforts, with low vaccination uptake, poor surveillance, vaccine hesitancy, lack of community engagement, weaknesses in the healthcare system and other challenges in Nigeria regionally and nationally, posing a risk to public health that threatens the eradication of all forms of polio in Nigeria. Conclusions: Recommendations are suggested for changes to practice and policy to improve polio vaccination uptake in Nigeria and globally in the short-term (1–2 years), mid-term (3–4 years) and long-term (5+ years). Collaborative targeted polio vaccination programs and funding of public health infrastructure are imperative globally alongside national strategic policy intervention frameworks to strengthen the World Health Organization Global Polio Eradication Initiative and improve vaccine uptake and monitoring of vaccine hesitancy. Simultaneous health-literate community engagement is needed to achieve and maintain polio eradication efforts, which must be integrated into national health frameworks and coordinated across the African continent. Full article

Background/Objectives: As we commemorate 50 years of the Expanded Programme on Immunization (EPI), the global mission to eradicate polio stands at a critical juncture. While remarkable progress has been made over the past decades, ensuring a steady supply of polio vaccines remains a significant challenge that could undermine these achievements. This manuscript aims to address the complexities of polio vaccine security within the context of the Immunization Agenda 2030 (IA2030) and the Global Polio Eradication Strategy 2022–2029, proposing actionable strategies to strengthen the vaccine supply. Methods: This manuscript analyzes obstacles to vaccine security, including supply disruptions and market uncertainties. It presents the Polio Vaccine Security Framework as a key strategy for addressing these challenges. Data were gathered from Global Polio Eradication Initiative (GPEI) reports, consultations with key stakeholders, and analyses of past vaccine shortages. Results: The findings indicate that the primary risks to vaccine security include the lack of a coherent long-term policy framework on polio vaccination, the absence of a clear polio vaccine development roadmap, and insufficient long-term, predictable forecasting. Additionally, stronger coordination is needed between stakeholders involved in vaccine supply, polio containment, and research, as well as addressing challenges related to financing and access to resources. Conclusions: A robust, adaptable, and sustainable approach to vaccine security, proposed in the Polio Vaccine Security Framework, is critical to achieving and sustaining polio eradication. Collaboration among policymakers, manufacturers, and stakeholders to implement it is essential to ensure the uninterrupted supply of polio vaccines, protecting the progress made over the past half century, and preventing a resurgence of poliovirus in the future. Full article

In the context of the near-global eradication of wild poliovirus, the significance of non-polio enteroviruses (NPEVs) in causing acute flaccid paralysis (AFP) and their impact on public health has gained increased attention. This research, conducted from 2001 to 2021, examined stool samples from 1597 children under 15 years in São Paulo, Brazil, through the AFP/Poliomyelitis Surveillance Program, detecting NPEVs in 6.9% of cases. Among the 100 NPEV-positive strains analyzed, 90 were genotyped through genomic sequencing of the partial VP1 region, revealing a predominance of EV-B species (58.9%), followed by EV-A (27.8%) and EV-C (13.3%). This study identified 31 unique NPEV types, including EV-A71, CVB2, and E11, as the most prevalent, along with the first documented occurrence of CVA19 in Brazil. These findings emphasize the importance of NPEV genotyping in distinguishing AFP from poliomyelitis, enhancing understanding of these viruses’ epidemiology. Moreover, it ensures that AFP cases are correctly classified, contributing to the effective surveillance and eradication efforts for poliomyelitis. Full article

The Global Polio Eradication Initiative (GPEI), launched in 1988, has successfully reduced wild poliovirus (WPV) cases by over 99.9%, with WPV type 2 and WPV3 declared eradicated in 2015 and 2019, respectively. However, as of 2024, WPV1 remains endemic in Afghanistan and Pakistan. Since 2000, outbreaks of circulating virus derived of polio vaccines (cVDPVs) have emerged in multiple regions, primary driven by low vaccine coverage rates (VCRs). The COVID-19 pandemic disrupted routine immunization, resulting in millions of unvaccinated children, and leaving many countries vulnerable to both WPV1 and cVDPVs outbreaks. This paper reviews the epidemiological landscape of poliomyelitis post the COVID-19 pandemic, and the strategies and challenges to achieve the global polio eradication. Full article

Background/Objectives: Although wild poliovirus type 2 has been eradicated, the prolonged transmission of the live- attenuated virus contained in the type-2 oral polio vaccine (OPV2) in under-immunized populations has led to the emergence of circulating vaccine-derived poliovirus type 2 (cVDPV2). The novel OPV2 (nOPV2) was designed to be more genetically stable and reduce the chance of cVDPV2 emergence while retaining comparable immunogenicity to the Sabin monovalent OPV2 (mOPV2). This study aimed to estimate the relative reduction in the emergence risk due to the use of nOPV2 instead of mOPV2. Methods: Data on OPV2 vaccination campaigns from May 2016 to 1 August 2024 were analyzed to estimate type-2 OPV-induced immunity in children under 5 years of age. Poliovirus surveillance data were used to estimate seeding dates and classify cVDPV2 emergences as mOPV2- or nOPV2-derived. The expected number of emergences if mOPV2 was used instead of nOPV2 was estimated, accounting for the timing and volume of nOPV2 doses, the known risk factors for emergence from mOPV2, and censoring due to the incomplete observation period for more recent nOPV2 doses. Results: As of 1 August 2024, over 98% of the approximately 1.19 billion nOPV2 doses administered globally were in Africa. We estimate that approximately 76 (95% confidence interval 69–85) index isolates of cVDPV2 emergences would be expected to be detected by 1 August 2024 if mOPV2 had been used instead of nOPV2 in Africa. The 18 observed nOPV2-derived emergences represent a 76% (74–79%) lower risk of emergence by nOPV2 than mOPV2 in Africa. The crude global analysis produced similar results. Key limitations include the incomplete understanding of the drivers of heterogeneity in emergence risk across geographies and variance in the per-dose risk of emergence may be incompletely captured using known risk factors. Conclusions: These results are consistent with the accumulating clinical and field evidence showing the enhanced genetic stability of nOPV2 relative to mOPV2, and this approach has been implemented in near-real time to contextualize new findings during the roll-out of this new vaccine. While nOPV2 has resulted in new emergences of cVDPV2, the number of cVDPV2 emergences is estimated to be approximately four-fold lower than if mOPV2 had been used instead. Full article

In the Global Poliovirus Laboratory Network (GPLN), participation and successful completion in annual proficiency test (PT) panels has been a part of the WHO accreditation process for decades. The PT panel is a molecular external quality assessment (mEQA) that evaluates laboratory preparedness, technical proficiency, the accuracy of data interpretation, and result reporting. Using the Intratypic Differentiation (ITD) real-time RT-PCR kits from CDC, laboratories run screening assays and report results in accordance with the ITD algorithm to identify and type polioviruses. The mEQA panels consisted of 10 blinded, non-infectious lyophilized RNA transcripts, including programmatically relevant viruses and targets contained in the real-time PCR assays. Sample identities included wildtype, vaccine-derived (VDPV), Sabin-like polioviruses, enterovirus, and negatives, as well as categories of invalid and indeterminate. The performance of individual laboratories was assessed based on the laboratory’s ability to correctly detect and characterize the serotype/genotype identities of each sample. The scoring scheme assessed the laboratory readiness following GPLN guidelines. Laboratories receiving mEQA scores of 90 or higher passed the assessment, scores of less than 90 failed and required remedial actions and re-evaluation. In 2021 and 2022, 123 and 129 GPLN laboratories were invited to request the annual PT panel, and 118 and 127 laboratories submitted results, respectively. The overall results were good, with 86% and 91.5% of laboratories passing the PT panel on their first attempt in 2021 and 2022, respectively. Most labs scored the highest score of 100, and less than one quarter scored between 90 and 95. Less than 10% of submitting laboratories failed the PT, resulting in in-depth troubleshooting to identify root causes and remediations. Most of these laboratories were issued a second PT panel for repeat testing, and almost all laboratories passed the repeat PT panel. The results of the 2021 and 2022 annual mEQA PTs showed that, despite the COVID-19 pandemic, the performance remained high in the GPLN, with most labs achieving the highest score. For these labs, the real-time PCR assay updates that were implemented during 2021–2022 were carried out with full adherence to procedures and algorithms. Even initially failing labs achieved passing scores after remediation. Full article

Pandemics of infectious disease and growing anti-microbial resistance (AMR) pose major threats to global health, trade, and security. Conflict and climate change compound and accelerate these threats. The One Health approach recognizes the interconnectedness of human, animal, and environmental health, but is grounded in the biomedical model, which reduces health to the absence of disease. Biomedical responses are insufficient to meet the challenges. The COVID-19 pandemic is the most recent example of the failure of this biomedical model to address global threats, the limitations of laboratory-based surveillance, and the exclusive focus on vaccination for disease control. This paper examines the current paradigm through the lens of polio and the global campaign to eradicate it, as well as other infectious threats including mpox and drug-resistant tuberculosis, particularly in the context of armed conflict. Decades before vaccines became widely available, public health measures—ventilation, chlorination, nutrition and sanitation— led to longer, healthier, and even taller lives. Chlorine, our primary tool of public health, conquered cholera and transformed infection control in hospitals. The World Health Organization (WHO), part of the One Health alliance, focuses mainly on antibiotics and vaccines to reduce deaths due to superbugs and largely ignores the critical role of chlorine to control water-borne diseases (including polio) and other infections. Moreover, the One Health approach ignores armed conflict. Contemporary wars are characterized by indiscriminate bombing of civilians, attacks targeting healthcare, mass displacement and lack of humanitarian access, conditions which drive polio outbreaks and incubate superbugs. We discuss the growing trend of attacks on healthcare and differentiate between types: community-driven attacks targeting vaccinators in regions like Pakistan, and state-sponsored attacks by governments such as those of Syria and Russia that weaponize healthcare to deliberately harm whole populations. Both fuel outbreaks of disease. These distinct motivations necessitate tailored responses, yet the WHO aggregates these attacks in a manner that hampers effective intervention. While antimicrobial resistance is predictable, the escalating pandemic is the consequence of our reliance on antibiotics and commitment to a biomedical model that now borders on pathological. Our analysis reveals the international indenture to the biomedical model as the basis of disease control is the root driver of AMR and vaccine-derived polio. The unique power of vaccines is reduced by vaccination-only strategy, and in fact breeds vaccine-derived polio. The non-specific effects of vaccines must be leveraged, and universal vaccination must be supplemented by international investment in water chlorination. This will reduce health costs and strengthen global health security. While vaccines are an important weapon to combat pandemics and AMR, they must be accompanied by the entire arsenal of public health interventions. Full article

Background: The serotype 2 oral poliovirus vaccine (OPV2) can revert to regain wild-type neurovirulence and spread, causing the emergence of vaccine-derived poliovirus (VDPV2) and immunodeficiency-related vaccine-derived polioviruses (iVDPVs). In the United States, testing carried out by the CDC of type II iVDPV (iVDPV2) with human immune serum from the vaccine has shown that the presence of the virus poses a threat to eradication efforts. Methods: We analyzed the major neutralization sites of VP1, VP2, and VP3 of the iVDPV using bioinformatics techniques and homology modeling (SWISS-MODEL). The three amino acid residues 679, 680, and 141 of the P1 region changed, which had an impact on the spatial conformation of the viral-neutralizing site. We tested polio-vaccinated human sera and rabbit anti-Sabin II polyantibodies against a panel of iVDPV pseudoviruses. Results: The results demonstrated that the serum’s capacity to neutralize mutant pseudoviruses diminished when amino acid substitutions were introduced into the P1 encapsidated protein, particularly when 141 and 679 were mutated together. This study emphasizes the significance of continually monitoring individuals who are known to be immunocompromised and maintaining high vaccination rates in OPV-using communities. Full article