Global Polio Eradication Initiative Research Articles

From legacy to integration in the Global Polio Eradication Initiative: looking back to look forward

IntroductionThe Global Polio Eradication Initiative (GPEI) is a global single-disease programme with an extensive infrastructure in some of the world’s most underserved areas. It provides a key example of the...

Polio Surge Capacity Support Program Contributions to Building Country Capacities in Support of Polio Outbreak Preparedness and Response: Lessons Learned and Remaining Challenges

Despite coordinated efforts at global level, through the Global Polio Eradication Initiative (GPEI), poliomyelitis disease (Polio) is still a major public health issue. The wild poliovirus type-1 (WPV1) is still endemic in Afghanistan and Pakistan, and new circulations of the WPV1 were confirmed in southeast Africa in 2021, in Malawi and Mozambique. The circulating vaccine derived polioviruses (cVDPV) are also causing outbreaks worldwide. The Task Force for Global Health (TFGH)’s Polio Surge Capacity Support Program, established in 2019, is an effort to reinforce the existing partnership with the GPEI to strengthen countries’ capacities for polio outbreak preparedness and response. In four years, its coordinated efforts with GPEI partners have resulted in a remarkable improvement in the early detection of poliovirus circulation and reducing the missed children gaps in many countries. However, these encouraging results cannot hide an increasingly complex programmatic environment with numerous funding and operational challenges.

The Immunogenicity of Monovalent Oral Poliovirus Vaccine Type 1 (mOPV1) and Inactivated Poliovirus Vaccine (IPV) in the EPI Schedule of India.

In 2016, the Global Polio Eradication Initiative (GPEI) recommended the cessation of using type 2 oral poliovirus vaccine (OPV) and OPV, with countries having to switch from the trivalent to bivalent OPV (bOPV) with the addition of inactivated poliovirus vaccine (IPV) in their routine immunization schedule. The current GPEI strategy 2022-2026 includes a bOPV cessation plan and a switch to IPV alone or a combination of vaccine schedules in the future. The focus of our study was to evaluate the immunogenicity of monovalent OPV type 1 (mOPV1) with IPV and IPV-only schedules. This was a three-arm, multi-center randomized-controlled trial conducted in 2016-2017 in India. Participants, at birth, were randomly assigned to the bOPV-IPV (Arm A) or mOPV1-IPV (Arm B) or IPV (Arm C) schedules. Serum specimens collected at birth and at 14, 18, and 22 weeks old were analyzed with a standard microneutralization assay for all the three poliovirus serotypes. The results of 598 participants were analyzed. The type 1 cumulative seroconversion rates four weeks after the completion of the schedule at 18 weeks were 99.5% (97.0-99.9), 100.0% (97.9-100.0), and 96.0% (92.0-98.1) in Arms A (4bOPV + IPV), B (4mOPV1 + IPV), and C (3IPV), respectively. Type 2 and type 3 seroconversions at 18 weeks were 80.0% (73.7-85.1), 76.9% (70.3-82.4); 93.2% (88.5-96.1), 100.0% (98.0-100.0); and 81.9% (75.6-86.8), 99.4% (96.9-99.9), respectively, in the three arms. This study shows the high efficacy of different polio vaccines for serotype 1 in all three schedules. The type 1 seroconversion rate of mOPV1 is non-inferior to bOPV. All the vaccines provide high type-specific immunogenicity. The program can adopt the use of different vaccines or schedules depending on the epidemiology from time to time.

The Last Mile in Polio Eradication: Program Challenges and Perseverance.

As the Global Polio Eradication Initiative (GPEI) strategizes towards the final steps of eradication, routine immunization schedules evolve, and high-quality vaccination campaigns and surveillance systems remain essential. New tools are consistently being developed, such as the novel oral poliovirus vaccine to combat outbreaks more sustainably, as well as non-infectiously manufactured vaccines such as virus-like particle vaccines to eliminate the risk of resurgence of polio on the eve of a polio-free world. As the GPEI inches towards eradication, re-strategizing in the face of evolving challenges and preparing for unknown risks in the post-certification era are critical.

Inactivated Poliovirus Vaccine: Recent Developments and the Tortuous Path to Global Acceptance.

Inactivated poliovirus vaccine (IPV), available since 1955, became the first vaccine to be used to protect against poliomyelitis. While the immunogenicity of IPV to prevent paralytic poliomyelitis continues to be irrefutable, its requirement for strong containment (due to large quantities of live virus used in the manufacturing process), perceived lack of ability to induce intestinal mucosal immunity, high cost and increased complexity to administer compared to oral polio vaccine (OPV), have limited its use in the global efforts to eradicate poliomyelitis. In order to harvest the full potential of IPV, a program of work has been carried out by the Global Polio Eradication Initiative (GPEI) over the past two decades that has focused on: (1) increasing the scientific knowledge base of IPV; (2) translating new insights and evidence into programmatic action; (3) expanding the IPV manufacturing infrastructure for global demand; and (4) continuing to pursue an ambitious research program to develop more immunogenic and safer-to-produce vaccines. While the knowledge base of IPV continues to expand, further research and product development are necessary to ensure that the program priorities are met (e.g., non-infectious production through virus-like particles, non-transmissible vaccine inducing humoral and intestinal mucosal immunity and new methods for house-to-house administration through micro-needle patches and jet injectors), the discussions have largely moved from whether to how to use this vaccine most effectively. In this review, we summarize recent developments on expanding the science base of IPV and provide insight into policy development and the expansion of IPV manufacturing and production, and finally we provide an update on the current priorities.

Population Immunity and Polio Eradication.

The Global Polio Eradication Initiative made immense progress after its establishment in 1988 as a consequence of high coverage with various poliovirus vaccines in all populations of the world. Problems have arisen in recent years, however, related to security issues in some countries, to the circulation of vaccine-derived polioviruses, and to the recognition that individuals with certain immune deficiencies can remain infected and infectious for many months or years. As natural infection and different vaccines have different effects on the immune system, the patterns of humoral and mucosal immunity to polioviruses in the world today are complex but are crucial to the ultimate success of the eradication initiative. This paper describes the background of the current situation and current immunological patterns and discusses their implications for managing population immunity to polioviruses in the years ahead.

Re-emergence of polio in Pakistan: Can the nation achieve the WPV1 eradication goal?

Poliomyelitis is an acute neurologic condition that causes muscle weakness, permanent flaccid paralysis, and even death. The world has seen a drastic fall in the number of poliovirus cases owing to effective immunization programs and preventive measures. Pakistan and Afghanistan still remain the two endemic countries for poliovirus, particularly, the WPV1 strain. Global Polio Eradication Initiative (GPEI) has set a target to eradicate all WPV1 cases by the end of 2023. However, the re-emergence of WPV1 cases has posed a serious setback for the achievement of this target. This article aims to discuss the public health challenges that contribute to resurgence of poliovirus cases. A comprehensive literature search was conducted using various databases including Cochrane, Google Scholar, PubMed, Science Direct, MEDLINE. Only articles written in English were considered. All the articles reporting the incidence of poliovirus and WPV1 cases in Pakistan, surveillance data and global context of poliovirus outbreak were evaluated to write this correspondence. In addition, references from the selected articles were also examined to ensure a comprehensive review of the literature. This article highlights the factors contributing to the re-emergence of WPV1 cases in Pakistan. Low vaccine coverage, attacks on frontline polio health workers, misinformation, and reluctance to vaccine acceptance pose a daunting challenge for polio eradication. Further, gaps in AFP surveillance and sensitivity may underestimate the true extent of the emerging genetic clusters. The Covid-19 pandemic and subsequent flooding in the affected area have further worsened the underdeveloped public health infrastructure. Despite the challenges, the country has observed a significant decline in the number of cases in the past 2 years. It is high time to capitalize on the decrease in WPV1 cases by intensifying the efforts to mitigate and limit the spread of the disease.

Leveraging global investments forpolio eradication to strengthen health systems' resilience through transition.

Since the launch of the Global Polio Eradication Initiative in 1988, more than US$20 billion has been invested globally in polio eradication. The World Health Organization and its partners are currently supporting Member States to transition the functions used to eradicate polio to strengthen their health systems. This study analyses global polio activities through the lens of health systems and the Common Goods for Health (CGH). Polio activities include key health system functions such as surveillance and response systems and immunization, which are essential to maintaining resilient health systems. They also support essential functions such as policy development, planning, training and capacity building, which are often underfunded in many countries. To improve overall resilience, it is critical to continue to integrate these functions into local health systems so that the capacity built through the polio eradication programme can be used for broader public health purposes. It is vital that this integration process be tailored to each country's unique health system context, rather than using a one-size-fits-all approach. While integration of all polio activities into local health systems is ideal, the transition to domestic financing may be coordinated with other global health financing mechanisms. This would reduce funding fragmentation and transaction costs, and allow for a focus on health system functions as a whole rather than just disease-specific efforts. The transition to domestic financing of polio activities could be staggered, prioritizing the transition to domestic funding for activities with limited global externalities, while seeking longer-term external funding for those that are global CGH.

Oral polio vaccine stockpile modeling: insights from recent experience

ABSTRACTBackgroundAchieving polio eradication requires ensuring the delivery of sufficient supplies of the right vaccines to the right places at the right times. Despite large global markets, decades of use, and large quantity purchases of polio vaccines by national immunization programs and the Global Polio Eradication Initiative (GPEI), forecasting demand for the oral poliovirus vaccine (OPV) stockpile remains challenging.Research design and methodsWe review OPV stockpile experience compared to pre-2016 expectations, actual demand, and changes in GPEI policies related to the procurement and use of type 2 OPV vaccines. We use available population and immunization schedule data to explore polio vaccine market segmentation, and its role in polio vaccine demand forecasting.ResultsWe find that substantial challenges remain in forecasting polio vaccine needs, mainly due to (1) deviations in implementation of plans that formed the basis for earlier forecasts, (2) lack of alignment of tactics/objectives among GPEI partners and other key stakeholders, (3) financing, and (4) uncertainty about development and licensure timelines for new polio vaccines and their field performance characteristics.ConclusionsMismatches between supply and demand over time have led to negative consequences associated with both oversupply and undersupply, as well as excess costs and potentially preventable cases.

Failure of poliomyelitis eradication campaign with oral vaccine: there's no vaccination without adherence

Thirty-five years after its launch, the Global Polio Eradication Initiative has yet to reach its original goal of 2000. Not only is the wild type 1 polio virus still endemic in two countries, but a new outbreak due to viruses derived from the live attenuated virus used for the oral vaccine has been spreading since 2016. The National Immunization Days (NID), during which teams go door-to-door and attract children to be vaccinated, have provoked violent opposition particularly in Northern Nigeria and in the area of India, Pakistan, Afghanistan. In both regions, the same rumor has developed that the vaccine contains sterilizing products, in order to limit the Muslim population. The organizers of the campaign multiplied in vain the NIDs to overcome the resistance, but pockets of insufficiently vaccinated population have persisted. This has allowed the wild virus to remain endemic and the new outbreak of vaccine-derived viruses to progress. We can wonder what the campaign would have become if its organizers had taken the time to reflect and reorient their strategy to rely on the routine vaccination of the Expanded Program on Immunization that does not arouse such opposition.

Evaluation of Direct Detection Protocols for Poliovirus from Stool Samples of Acute Flaccid Paralysis Patients.

Polio surveillance in the Global Polio Eradication Initiative has been conducted with virus isolation from stool samples of acute flaccid paralysis (AFP) cases. Under the current biorisk management/regulations, challenges arise in the timelines of the report, sensitivity of the test and containment of poliovirus (PV) isolates. In the present study, we evaluated protocols of previously reported direct detection (DD) methods targeting the VP1 or VP4-VP2 regions of the PV genome in terms of sensitivity and sequencability. An optimized protocol targeting the entire-capsid region for the VP1 sequencing showed a high sensitivity (limit of detection = 82 copies of PV genome) with a simpler and faster reaction than reported ones (i.e., with the addition of all the primers at the start of the reaction, the RT-PCR reaction finishes within 2.5 h). The DD methods targeting the VP1 region detected PV in 60 to 80% of PV-positive stool samples from AFP cases; however, minor populations of PV strains in the samples with virus mixtures were missed by the methods. Sequencability of the DD methods was primarily determined by the efficiency of the PCRs for both Sanger and nanopore sequencing. The DD method targeting the VP4-VP2 region showed higher sensitivity than that targeting the VP1 region (limit of detection = 25 copies of PV genome) and successfully detected PV from all the stool samples examined. These results suggest that DD methods are effective for the detection of PV and that further improvement of the sensitivity is essential to serve as an alternative to the current polio surveillance algorithm.

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2022-June 2023.

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was reported in 125 countries. Since 2017, Afghanistan and Pakistan remain the only countries with uninterrupted endemic WPV type 1 (WPV1) transmission. This report describes activities and progress toward polio eradication in Afghanistan during January 2022-June 2023. Two WPV1 cases were reported during January-December 2022 and five during January-June 2023 (as of August 26), all from three provinces in the southeast and east regions bordering Pakistan. All five 2023 patients had reportedly received ≥16 oral poliovirus vaccine doses. WPV1 was detected in sewage samples from a site in the south region in May 2023 and one in the north region in June 2023, the first detections since February 2021 and March 2020, respectively. Restrictions on house-to-house vaccination limit the effectiveness of vaccination campaigns in parts of the south and northeast regions. Because of population movement, the risk for transmission in Afghanistan and Pakistan will remain if WPV1 circulation continues in either country. Despite operational improvements in vaccination activities, interruption of WPV1 transmission in Afghanistan will require committed, uninterrupted efforts, including ongoing coordination with Pakistan on polio eradication activities, to address vaccination coverage gaps that sustain WPV1 circulation.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2022-June 2023.

Since the establishment of the Global Polio Eradication Initiative in 1988, Pakistan remains one of only two countries (along with Afghanistan) with continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress toward polio eradication during January 2022-June 2023. During 2022, Pakistan reported 20 WPV type 1 (WPV1) cases, all of which occurred within a small geographic area encompassing three districts in south Khyber Pakhtunkhwa. As of June 23, only a single WPV1 case from Bannu district in Khyber Pakhtunkhwa province has been reported in 2023, compared with 13 cases during the same period in 2022. In addition, 11 WPV1 isolates have been reported from various environmental surveillance (ES) sewage sampling sites to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographic scope of poliovirus circulation in Pakistan, the isolation of WPV1 from an ES site in Karachi is cause for concern about the actual geographic limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained innovative efforts to vaccinate children who are regularly missed during SIAs and rapidly responding to any new WPV1 isolations.

Setbacks faced by the Global Polio Eradication Initiative (GPEI) in low-income countries and rectifications needed.

Setbacks faced by the Global Polio Eradication Initiative (GPEI) in low-income countries and rectifications needed.

Retinopathy of prematurity in India - what can we learn from the polio legacy?

Retinopathy of prematurity (ROP) is a vasoproliferative disease of the preterm retina that has the potential to cause vision impairment and blindness. Timely screening and treatment are hence critical for infants at risk for ROP. Screening for ROP is challenging in India owing to the limited resources, a vast at-risk population and lack of awareness among paediatricians and the public. Addressing ROP in India requires a comprehensive approach involving multiple sectors, considering the magnitude of the problem and the expected increase in need for ROP services due to the increased survival of preterm infants following improvements in neonatal care. The success of the Global Polio Eradication Initiative (GPEI) offers valuable lessons for improving ROP services in developing nations by applying its strategies. An approach for primary and secondary prevention of ROP is proposed, and the current challenges and a neonatal-led care model for ROP are discussed.

The Elephant’s Tail of VAPP, VDPV in the Polio End Game

A lot have been achieved by the Global Polio Eradication Initiative since 1988 after World Health Assembly passed the resolution to eradicate polio. Today, we have decreased the global polio incidence by 99.9% since GPEIs started working. We still have to remove polio from the few leftover pockets and get rid of the final 0.1% of polio cases. We have gained in positive terms that an estimated 16 million people today are walking and more than 1.5 million are alive because of the stakeholders’ strong, strategic and cooperative action. The journey to the last mile has some different difficulties and this article tries to provide additional insights into the strategies to achieve our goal of Polio eradication.

Worst-case scenarios: Modeling uncontrolled type 2 polio transmission.

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.

Surveillance To Track Progress Toward Poliomyelitis Eradication — Worldwide, 2021–2022

Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of wild poliovirus (WPV) cases has declined by >99.9%, and WPV serotypes 2 and 3 have been declared eradicated (1). By the end of 2022, WPV type 1 (WPV1) transmission remained endemic only in Afghanistan and Pakistan (2,3). However, during 2021-2022, Malawi and Mozambique reported nine WPV1 cases that were genetically linked to Pakistan (4,5), and circulating vaccine-derived poliovirus (cVDPV) outbreaks were detected in 42 countries (6). cVDPVs are oral poliovirus vaccine-derived viruses that can emerge after prolonged circulation in populations with low immunity allowing reversion to neurovirulence and can cause paralysis. Polioviruses are detected primarily through surveillance for acute flaccid paralysis (AFP), and poliovirus is confirmed through stool specimen testing. Environmental surveillance, the systematic sampling of sewage and testing for the presence of poliovirus, supplements AFP surveillance. Both surveillance systems were affected by the COVID-19 pandemic's effects on public health activities during 2020 (7,8) but improved in 2021 (9). This report updates previous reports (7,9) to describe surveillance performance during 2021-2022 in 34 priority countries.* In 2022, a total of 26 (76.5%) priority countries met the two key AFP surveillance performance indicator targets nationally compared with 24 (70.6%) countries in 2021; however, substantial gaps remain in subnational areas. Environmental surveillance expanded to 725 sites in priority countries, a 31.1% increase from the 553 sites reported in 2021. High-quality surveillance is critical to rapidly detect poliovirus transmission and enable prompt poliovirus outbreak response to stop circulation. Frequent monitoring of surveillance guides improvements to achieve progress toward polio eradication.

Polio-philanthropy in Africa: A narrative review.

Polio eradication efforts including polio-philanthropy have been coordinated and sustained since 1988, with the introduction of the Global Polio Eradication Initiative (GPEI). The polio fight is sustained in the name of evidence-based benevolence or beneficent philanthropy from which Africa has benefited immensely. With the recorded polio cases as of 2023, more efforts and funds are required to eradicate polio. Hence, it is not yet "Uhuru." Using the Mertonian lens, this study examines polio-philanthropy in Africa, its unintended consequences, and crucial dilemmas, which could impact the polio fight and polio-philanthropy. This is a narrative review that relies on secondary sources obtained through a thorough literature search. Only studies published in English were utilized. The study synthesized relevant literature in line with the study objective. The following databases were consulted: PubMed, philosopher's index, web of knowledge, Google Scholar, and Sociological Abstracts. Both empirical and theoretical studies were utilized for the study. Despite significant achievements, the global initiative has shortcomings when examined through the Mertonian lens of manifest and latent functions. The GPEI sets a unilinear goal within multiple challenges. The activities of the philanthropic giants manifest in disempowering rigor, multisectoral neglect, and parallel (health) systems, sometimes, inimical to the national health system. Most philanthropic giants often operate vertically. It is observed that, apart from funding, the last phase of polio-philanthropy will be defined by some crucial factors, the 4Cs: Communicable disease outbreaks, Conflict, Climate-related disasters, and Conspiracy theory, which could impact the prevalence or resurgence of polio. The polio fight will benefit from the persistent drive to reach the finish line as scheduled. The latent consequences or dysfunctions are general lessons for GPEI and other global health initiatives. Therefore, decision-makers should calculate the net balance of consequences within global health philanthropy for appropriate mitigation.

From Polio to COVID-19: Examining the Impact of Pandemics on Childhood Vaccination Programs.

This review article aims to examine the impact of pandemics on childhood vaccination programs, specifically looking at the examples of polio and coronavirus disease 2019 (COVID-19). The article provides a comprehensive overview of the history of polio vaccination programs, including the challenges of eradicating the disease and the barriers to vaccine uptake. The article also looks at the global efforts to eradicate polio, such as the Global Polio Eradication Initiative, and the progress made in reducing the number of polio cases worldwide. The article reviews the impact of the COVID-19 pandemic on childhood vaccination programs and how the pandemic has disrupted routine vaccination services. Lockdowns and travel restrictions have contributed to this, which has reduced access to medical facilities and vaccine uptake.The article also explores how the prioritization of COVID-19 vaccines has led to a diversion of resources away from routine childhood immunization programs. The article highlights the need to address these challenges to prevent a resurgence of vaccine-preventable diseases. Furthermore, the article discusses the lessons learned from these pandemics, such as the importance of global collaboration, vaccine equity, addressing vaccine hesitancy, pandemic preparedness, and embracing technology. The article emphasizes the need to prioritize vaccine equity andensure that vulnerable populations have access to vaccines. Additionally, the article stresses the importance of addressing vaccine hesitancy and providing effective communication and education about vaccines. The article also advocates for pandemic preparedness, emphasizing the need to invest in research and development of vaccines for emerging infectious diseases. Finally, the article suggests embracing technology as a means to improve vaccine accessibility and distribution.