Global polio eradication; can we replicate the smallpox success story?

Although the Global Polio Eradication Initiative has been largely successful in elimination of polio from various parts of the world, sporadic local outbreaks in non-endemic areas continue to pose a threat to global polio eradication efforts. In the two endemic countries, Pakistan and Afghanistan, a staggering 176 cases of wild poliovirus 1 (WPV1) were reported in 2019. In 2020 alone, 959 cases of Circulating Vaccine Derived Poliovirus 2 were reported globally from 27 countries. After staying polio-free for years, cases of WPV were detected in Malawi and Mozambique in 2022. The roots of the reported strains matched with the WPV strain from Pakistan. The emergence of WPV cases in Malawi and Mozambique underscores the fact that WPV still has the chance to spread beyond the Afghanistan-Pakistan region and sustained efforts are required for its complete eradication. In the case of smallpox, surveillance-containment was the key to eradication as many countries had already eradicated smallpox and the bigger concern was to track and contain any new cases emerging. Smallpox eradication followed a comprehensive plan which included elements like quality control and standardisation of vaccination protocols. Governments all over the world should prioritise immunisation drives, surveillance, and awareness campaigns to achieve the dream of a polio-free world.

Evaluation of 17 years of MERIN (Meningitis and Encephalitis register in Lower Saxony, Germany) surveillance system: participants acceptability survey, completeness and timeliness of data.

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.

Conserved Antigenic Structure of Contemporary Wild Poliovirus Type 1 Strains Endemic in Pakistan.

BACKGROUND: Elimination of poliovirus in Pakistan and Afghanistan is challenged by notions against the role of oral poliovirus vaccine (OPV) in eradicating contemporary wild poliovirus (WPV) strains. METHODS: A total of 1055 WPV type 1 (WPV1) strains isolated between 2013 and 2018 were categorized into 68 antigenic groups and tested for neutralization by OPV-derived antibodies. Molecular docking was conducted to determine neutralization efficiency of antibodies against WPV. The clinical significance of WPV1 variants was assessed to ascertain their role in patient outcomes. RESULTS: We found that 88% of WPV1 strains isolated from paralytic children belonged to a single antigenic lineage identical to the WPV1 strain detected in 1993. WPV1 antigenic variants were effectively neutralized by OPV-derived antibodies, with geometric mean titers comparable to the neutralization titers found for 3 strains in OPV (OPV1-3, 7.96-9.149 [95% confidence interval, 6.864-10.171]; WPV1 strains, 7.542-8.786 [6.493-9.869]). Docking examination underscored a strong antigen-antibody interaction despite variations within the viral protein 1 epitopes. There was no significant association (P = .78) with clinical prognosis among patients infected with antigenically diverse WPV1 strains and patient outcomes, including death. CONCLUSIONS: Our findings substantiate the robustness of OPV for neutralizing the contemporary WPV1 strains endemic in Pakistan and Afghanistan. Vaccination coverage must be augmented to achieve early eradication.

How service delivery implementation strategies can contribute to attaining universal health coverage: lessons from polio eradication using an implementation science approach.

BACKGROUND: Improving service delivery is a key strategy for achieving service coverage, one of the two components of universal health coverage (UHC). As one of the largest global public health initiatives, individuals involved with the Global Polio Eradication Initiative (GPEI) have learned many important lessons about service delivery. We identified contributors and challenges to delivering health services at national and subnational levels using experiences from the GPEI. We described strategies used to strengthen service delivery and draw lessons that could be applicable to achieving UHC. METHODS: Online cross-sectional surveys based on the Consolidated Framework for Implementation Research (CFIR) domains and socioecological model were conducted from 2018-2019. Data were analyzed using an embedded mixed methods approach. Frequencies of the contributors and challenges to service delivery by levels of involvement were estimated. Chi-square tests of independence were used to assess unadjusted associations among categorical outcome variables. Logistic regressions were used to examine the association between respondent characteristics and contributors to successful implementation or implementation challenges. Horizontal analysis of free text responses by CFIR domain was done to contextualize the quantitative results. RESULTS: Three thousand nine hundred fifty-five people responded to the online survey which generated 3,659 valid responses. Among these, 887 (24.2%) reported involvement in service delivery at the global, national, or subnational level with more than 90% involved at subnational levels. The main internal contributor of strengthened service delivery was the process of conducting activities (48%); working in frontline role had higher odds of identifying the process of conducting activities as the main internal contributor (AOR: 1.22, p = 0.687). The main external contributor was the social environment (42.5%); having 10-14 years of polio program implementation was significantly associated with identifying the social environment as the main external contributor to strengthened service delivery (AOR: 1.61, p = 0.038). The most frequent implementation challenge was the external environment (56%); working in Eastern Mediterranean region was almost 4 times more likely to identify the external environment as the major challenge in service delivery strengthening (AOR:3.59, p < 0.001). CONCLUSION: Priority actions to improve service delivery include: adopt strategies to systematically reach hard-to-reach populations, expand disease-focused programs to support broader primary healthcare priorities, maximize community outreach strategies to reach broader age groups, build community trust in health workers and develop multisectoral leadership for collaboration. Achieving UHC is contingent on strengthened subnational service delivery.

Immunization Against Poliomyelitis and the Challenges to Worldwide Poliomyelitis Eradication.

Both inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV) have contributed to the rapid disappearance of paralytic poliomyelitis from developed countries despite possessing different vaccine properties. Due to cost, ease of use, and other properties, the Expanded Programme on Immunization added OPV to the routine infant immunization schedule for low-income countries in 1974, but variable vaccine uptake and impaired immune responses due to poor sanitation limited the impact. Following launch of the Global Polio Eradication Initiative in 1988, poliomyelitis incidence has been reduced by >99% and types 2 and 3 wild polioviruses are now eradicated, but progress against type 1 polioviruses which are now confined to Afghanistan and Pakistan has slowed due to insecurity, poor access, and other problems. A strategic, globally coordinated replacement of trivalent OPV with bivalent 1, 3 OPV in 2016 reduced the incidence of vaccine-associated paralytic poliomyelitis (VAPP) but allowed the escape of type 2 vaccine-derived polioviruses (VDPV2) in areas with low immunization rates and use of monovalent OPV2 in response seeded new VDPV2 outbreaks and reestablishment of type 2 endemicity. A novel, more genetically stable type 2 OPV vaccine is undergoing clinical evaluation and may soon be deployed prevent or reduce VDPV2 emergences.

Potential Future Use, Costs, and Value of Poliovirus Vaccines.

Countries face different poliovirus risks, which imply different benefits associated with continued and future use of oral poliovirus vaccine (OPV) and/or inactivated poliovirus vaccine (IPV). With the Global Polio Eradication Initiative (GPEI) continuing to extend its timeline for ending the transmission of all wild polioviruses and to introduce new poliovirus vaccines, the polio vaccine supply chain continues to expand in complexity. The increased complexity leads to significant uncertainty about supply and costs. Notably, the strategy of phased OPV cessation of all three serotypes to stop all future incidence of poliomyelitis depends on successfully stopping the transmission of all wild polioviruses. Countries also face challenges associated with responding to any outbreaks that occur after OPV cessation, because stopping transmission of such outbreaks requires reintroducing the use of the stopped OPV in most countries. National immunization program leaders will likely consider differences in their risks and willingness-to-pay for risk reduction as they evaluate their investments in current and future polio vaccination. Information about the costs and benefits of future poliovirus vaccines, and discussion of the complex situation that currently exists, should prove useful to national, regional, and global decisionmakers and support health economic modeling. Delays in achieving polio eradication combined with increasing costs of poliovirus vaccines continue to increase financial risks for the GPEI.

Updated Characterization of Post-OPV Cessation Risks: Lessons from 2019 Serotype 2 Outbreaks and Implications for the Probability of OPV Restart.

After the globally coordinated cessation of any serotype of oral poliovirus vaccine (OPV), some risks remain from undetected, existing homotypic OPV-related transmission and/or restarting transmission due to several possible reintroduction risks. The Global Polio Eradication Initiative (GPEI) coordinated global cessation of serotype 2-containing OPV (OPV2) in 2016. Following OPV2 cessation, the GPEI and countries implemented activities to withdraw all the remaining trivalent OPV, which contains all three poliovirus serotypes (i.e., 1, 2, and 3), from the supply chain and replace it with bivalent OPV (containing only serotypes 1 and 3). However, as of early 2020, monovalent OPV2 use for outbreak response continues in many countries. In addition, outbreaks observed in 2019 demonstrated evidence of different types of risks than previously modeled. We briefly review the 2019 epidemiological experience with serotype 2 live poliovirus outbreaks and propose a new risk for unexpected OPV introduction for inclusion in global modeling of OPV cessation. Using an updated model of global poliovirus transmission and OPV evolution with and without consideration of this new risk, we explore the implications of the current global situation with respect to the likely need to restart preventive use of OPV2 in OPV-using countries. Simulation results without this new risk suggest OPV2 restart will likely need to occur (81% of 100 iterations) to manage the polio endgame based on the GPEI performance to date with existing vaccine tools, and with the new risk of unexpected OPV introduction the expected OPV2 restart probability increases to 89%. Contingency planning requires new OPV2 bulk production, including genetically stabilized OPV2 strains.

Synthesis and translation of research and innovations from polio eradication (STRIPE): initial findings from a global mixed methods study.

BACKGROUND: Lessons from polio eradication efforts and the Global Polio Eradication Initiative (GPEI) are useful for improving health service delivery and outcomes globally. The Synthesis and Translation of Research and Innovations from Polio Eradication (STRIPE) is a multi-phase project which aims to map, package and disseminate knowledge from polio eradication initiatives as academic and training programs. This paper discusses initial findings from the knowledge mapping around polio eradication activities across a multi-country context. METHODS: The knowledge mapping phase (January 2018 - December 2019) encompassed four research activities (scoping review, survey, key informant interviews (KIIs), health system analyses). This paper utilized a sequential mixed method design combining data from the survey and KIIs. The survey included individuals involved in polio eradication between 1988 and 2019, and described the contexts, implementation strategies, intended and unintended outcomes of polio eradication activities across levels. KIIs were conducted among a nested sample in seven countries (Afghanistan, Bangladesh, the Democratic Republic of Congo, Ethiopia, India, Indonesia, Nigeria) and at the global level to further explore these domains. RESULTS: The survey generated 3955 unique responses, mainly sub-national actors representing experience in over 74 countries; 194 KIIs were conducted. External factors including social, political, and economic factors were the most frequently cited barriers to eradication, followed by the process of implementing activities, including program execution, planning, monitoring, and stakeholder engagement. Key informants described common strategies for addressing these barriers, e.g. generating political will, engaging communities, capacity-building in planning and measurement, and adapting delivery strategies. The polio program positively affected health systems by investing in system structures and governance, however, long-term effects have been mixed as some countries have struggled to institutionalize program assets. CONCLUSION: Understanding the implementing context is critical for identifying threats and opportunities to global health programs. Common implementation strategies emerged across countries; however, these strategies were only effective where organizational and individual capacity were sufficient, and where strategies were appropriately tailored to the sociopolitical context. To maximize gains, readiness assessments at different levels should predate future global health programs and initiatives should consider system integration earlier to ensure program institutionalization and minimize system distortions.

Lessons learned from the polio eradication initiative in the Democratic Republic of Congo and Ethiopia: analysis of implementation barriers and strategies.

BACKGROUND: Since its inception in 1988, the Global Polio Eradication Initiative (GPEI) has partnered with 200 countries to vaccinate over 2.5 billion children against poliomyelitis. The polio eradication approach has adapted to emerging challenges and diverse contexts. Knowledge assets gained from these experiences can inform implementation of future health programs, but only if efforts are made to systematically map barriers, identify strategies to overcome them, identify unintended consequences, and compare experiences across country contexts. METHODS: A sequential explanatory mixed methods design, including an online survey followed by key informant interviews (KIIs), was utilized to map tacit knowledge derived from the polio eradication experience from 1988 to 2019. The survey and KIIs were conducted between September 2018 and March 2019. A cross-case comparison was conducted of two study countries, the Democratic Republic of Congo (DRC) and Ethiopia, which fit similar epidemiological profiles for polio. The variables of interest (implementation barriers, strategies, unintended consequences) were compared for consistencies and inconsistencies within and across the two country cases. RESULTS: Surveys were conducted with 499 and 101 respondents, followed by 23 and 30 KIIs in the DRC and Ethiopia, respectively. Common implementation barriers included accessibility issues caused by political insecurity, population movement, and geography; gaps in human resources, supply chain, finance and governance; and community hesitancy. Strategies for addressing these barriers included adapting service delivery approaches, investing in health systems capacity, establishing mechanisms for planning and accountability, and social mobilization. These investments improved system infrastructure and service delivery; however, resources were often focused on the polio program rather than strengthening routine services, causing community mistrust and limiting sustainability. CONCLUSIONS: The polio program investments in the DRC and Ethiopia facilitated program implementation despite environmental, system, and community-level barriers. There were, however, missed opportunities for integration. Remaining pockets of low immunization coverage and gaps in surveillance must be addressed in order to prevent importation of wild poliovirus and minimize circulating vaccine-derived poliovirus. Studying these implementation processes is critical for informing future health programs, including identifying implementation tools, strategies, and principles which can be adopted from polio eradication to ensure health service delivery among hard-to-reach populations. Future disease control or eradication programs should also consider strategies which reduce parallel structures and define a clear transition strategy to limit long-term external dependency.

Strengthening National Immunization Technical Advisory Groups in resource-limited settings: current and potential linkages with polio national certification committees.

BACKGROUND: Countries are transitioning assets and functions from polio eradication to integrated immunization and surveillance activities. We assessed the extent of linkages between and perceptions of National Immunization Technical Advisory Groups (NITAGs) and National Certification Committees (NCCs) for polio eradication to understand how linkages can be leveraged to improve efficiencies of these expert bodies. METHODS: During May 2017 to May 2018, we administered a 15-question survey to a NITAG chair or member and an NCC counterpart in all countries of the WHO Regions for Africa (AFR) and for the Eastern Mediterranean (EMR) that had both a NITAG and an NCC. Data were analysed using frequency distributions. RESULTS: Of countries with both a NITAG and an NCC (n = 44), the response rate was 92% (22/24) in AFR and 75% (15/20) in EMR. Some respondents reported being very familiar with the functions of the other technical bodies, 36% (8/22) for NITAG members and 38% (14/37) for NCC members. Over 85% (51/59) of respondents felt it was somewhat useful or very useful to strengthen ties between bodies. Nearly all respondents (98%, 58/59) felt that NCC expertise could inform measles and rubella elimination programmes. CONCLUSIONS: We observed a broad consensus that human resource assets of NCCs may serve an important technical role to support national immunization policy-making. At this stage of the polio eradication initiative, countries should consider how to integrate the technical expertise of NCC members to reinforce NITAGs and maintain the polio essential functions, beginning in countries that have been polio-free for several years.

Achieving the end game: employing "vaccine diplomacy" to eradicate polio in Pakistan.

BACKGROUND: On April 28, 2014, the World Health Organization (WHO) declared polio a "Public Health Emergency of International Concern" (PHIC) under the authority of the International Health Regulations. Although polio has been eradicated from nearly every nation on earth, Pakistan is one of three countries where wild polio and vaccine-derived polio strains remain, thwarting global eradication efforts. AIMS: Polio eradication progress is complicated by security and conflict issues at the border area between Pakistan and Afghanistan. In addition to security issues, other critical challenges, such as maintaining cold supply chain for vaccines, active and sentinel surveillance, false beliefs about vaccines, distrust of healthcare workers, and accessibility to conflict areas due to terrorist activities, all play a role in the continued persistence of Polio. In response to these challenges, we assess the local and international policy environment and its impact on polio eradication in Pakistan. FINDINGS: Based on our analysis of existing barriers and challenges associated with polio eradication in Pakistan, this study discusses why employing "vaccine diplomacy" represents a key policy and advocacy strategic approach to achieve the overall end game of polio eradication. Specifically, we identify a set of concrete public health, international development, and diplomatic and policy recommendations that can act synergistically under the umbrella of health and vaccine diplomacy to finally put an end to polio.

Evaluation of Proactive and Reactive Strategies for Polio Eradication Activities in Pakistan and Afghanistan.

Only Pakistan and Afghanistan reported any polio cases caused by serotype 1 wild polioviruses (WPV1s) in 2017. With the dwindling cases in both countries and pressure to finish eradication with the least possible resources, a danger exists of inappropriate prioritization of efforts between the two countries and insufficient investment in the two countries to finish the job. We used an existing differential-equation-based poliovirus transmission and oral poliovirus (OPV) evolution model to simulate a proactive strategy to stop transmission, and different hypothetical reactive strategies that adapt the quality of supplemental immunization activities (SIAs) in response to observed polio cases in Pakistan and Afghanistan. To account for the delay in perception and adaptation, we related the coverage of the SIAs in high-risk, undervaccinated subpopulations to the perceived (i.e., smoothed) polio incidence. Continuation of the current frequency and quality of SIAs remains insufficient to eradicate WPV1 in Pakistan and Afghanistan. Proactive strategies that significantly improve and sustain SIA quality lead to WPV1 eradication and the prevention of circulating vaccine-derived poliovirus (cVDPV) outbreaks. Reactive vaccination efforts that adapt moderately quickly and independently to changes in polio incidence in each country may succeed in WPV1 interruption after several cycles of outbreaks, or may interrupt WPV1 transmission in one country but subsequently import WPV1 from the other country or enable the emergence of cVDPV outbreaks. Reactive vaccination efforts that adapt independently and either more rapidly or more slowly to changes in polio incidence in each country may similarly fail to interrupt WPV1 transmission and result in oscillations of the incidence. Reactive strategies that divert resources to the country of highest priority may lead to alternating large outbreaks. Achieving WPV1 eradication and subsequent successful OPV cessation in Pakistan and Afghanistan requires proactive and sustained efforts to improve vaccination intensity in under-vaccinated subpopulations while maintaining high population immunity elsewhere.

Low Rates of Poliovirus Antibodies in Primary Immunodeficiency Patients on Regular Intravenous Immunoglobulin Treatment.

PURPOSE: Poliovirus has been nearly eliminated as part of a world-wide effort to immunize and contain circulating wild-type polio. Nevertheless, poliovirus has been detected in water supplies and represents a threat to patients with humoral immunodeficiencies where infection can be fatal. To define the risk, we analyzed antibodies to poliovirus 1, 2, and 3 in serum samples collected over a year from patients with primary immunodeficiency diseases (PID) on regular intravenous immunoglobulin (IVIG) replacement. METHODS: Twenty-one patients on regular IVIG replacement therapy were evaluated: Twelve patients with common variable immune deficiency (CVID), six with X-linked agammaglobulinemia (XLA), and three with hyper IgM syndrome (HIGM). Over 1 year, four blood samples were collected from each of these patients immediately before immunoglobulin infusion. One sample of IVIG administered to each patient in the month before blood collection was also evaluated. Poliovirus antibodies were quantified by seroneutralization assay. RESULTS: All IVIG samples had detectable antibodies to the three poliovirus serotypes. Despite that, only 52.4, 61.9, and 19.0% of patients showed protective antibody titers for poliovirus 1, 2, and 3, respectively. Only two patients (9.5%) had protective antibodies for the three poliovirus serotypes on all samples. Most patients were therefore susceptible to all three poliovirus serotypes. CONCLUSIONS: This study demonstrates the need for ongoing vigilance regarding exposure of patients with PID to poliovirus in the community.

Diagnostic Assay Development for Poliovirus Eradication.

With poliovirus eradication nearing, few pockets of active wild poliovirus (WPV) transmission remain in the world. Intratypic differentiation (ITD) plays a crucial part in laboratory surveillance as the molecular detection method that can identify and distinguish wild and vaccine-like polioviruses isolated from acute flaccid paralysis cases or environmental sources. The need to detect new variants of WPV serotype 1 (WPV1) and the containment of all serotype 2 polioviruses (PV2) in 2015 required changes to the previous version of the method. The ITD version 5.0 is a set of six real-time reverse transcription-PCR (rRT-PCR) assays that serve as accurate diagnostic tools to easily detect and differentiate PV serotypes and genotypes. We describe the creation and properties of quantitation standards, including 16 control RNA transcripts and nine plaque-isolated viruses. All ITD rRT-PCR assays were validated using these standards, and the limits of detection were determined for each assay. We designed and pilot tested two new assays targeting recently circulating WPV1 genotypes and all PV2 viruses. The WPV1 assay had 99.1% specificity and 100% sensitivity, and the PV2 assay had 97.7% specificity and 92% sensitivity. Before proceeding to the next step in the global poliovirus eradication program, we needed to gain a better understanding of the performance of the ITD 5.0 suite of molecular assays and their limits of detection and specificities. The findings and conclusions in this evaluation serve as building blocks for future development work.

Vaccine-associated paralytic poliomyelitis in a patient with acute lymphocytic leukemia.

We report a case of vaccine-associated paralytic poliomyelitis (VAPP) in an immunocompromised patient with acute lymphocytic leukemia who was initially diagnosed with aseptic meningitis. Isolation of Sabin-like type 1 poliovirus from the patient's cerebrospinal fluid made this a case of vaccine-related poliovirus (VRPV) infection. The patient developed paralysis and respiratory distress and deceased a few months after onset of paralysis with respiratory failure. This tragic case report highlights the emergence of VAPP and indicates the importance of timely diagnosis of VRPV infections to improve clinical management of VRPV-infected patients and to prevent the devastating consequences of silent introduction of VRPVs in treatment wards and eventually in the society.

Assessing the potency and immunogenicity of inactivated poliovirus vaccine after exposure to freezing temperatures.

According to manufacturers, inactivated poliovirus vaccines (IPVs) are freeze sensitive and require storage between 2°C and 8°C, whereas oral poliovirus vaccine requires storage at -20 °C. Introducing IPV into ongoing immunization services might result in accidental exposure to freezing temperatures and potential loss of vaccine potency. To better understand the effect of freezing IPVs, samples of single-dose vaccine vials from Statens Serum Institut (VeroPol) and multi-dose vaccine vials from Sanofi Pasteur (IPOL) were exposed to freezing temperatures mimicking what a vaccine vial might encounter in the field. D-antigen content was measured to determine the in vitro potency by ELISA. Immunogenicity testing was conducted for a subset of exposed IPVs using the rat model. Freezing VeroPol had no detectable effect on in vitro potency (D-antigen content) in all exposures tested. Freezing of the IPOL vaccine for 7 days at -20 °C showed statistically significant decreases in D-antigen content by ELISA in poliovirus type 1 (p < 0.0001) and type 3 (p = 0.048). Reduction of poliovirus type 2 potency also approached significance (p = 0.062). The observed loss in D-antigen content did not affect immunogenicity in the rat model. Further work is required to determine the significance of the loss observed and the implications for vaccine handling policies and practices.

Distribution pattern of poliovirus potentially infectious materials in the phase 1b medical laboratories containment in conformity with the global action plan III.

BACKGROUND: The containment of poliovirus infectious/potentially infectious materials in all biomedical facilities in Nigeria remain crucial to maintaining gains recorded towards polio eradication. Activities involved in the Nigerian Poliovirus type 2-laboratory containment survey in line with the 3rd Global Action Plan III (GAP III) for poliovirus containment are documented in this study. Through these activities, the overall preparedness for poliovirus eradication in Nigeria is assessed. METHOD: A cross-sectional survey was conducted from 19th September-31st October 2016 using structured Laboratory survey and inventory (LSI) questionnaires uploaded onto the SPSS software package in 560 biomedical facilities classified either as high risk or medium risk facilities across the 6 zones in Nigeria. RESULTS: In total, 560 biomedical facilities were surveyed in Nigeria in conformity with the GAP III. In total, 86% of the facilities surveyed were with laboratories while 14% were without laboratories. Twelve laboratories with poliovirus potentially infectious materials were identified in this exercise. In total, 50% of the 12 laboratories were under the ministry of education for research purposes. While 33% were among those laboratories surveyed in the phase 1a exercise without any recorded inventory, but have acquired some since the phase 1a survey. A total of 13,484 poliovirus infectious materials were found in the 12 laboratories. Only 8% of the materials were immediately destroyed while the remaining materials (62%) were found in Oyo and Borno states scheduled for destruction within 3-4 months according to WHO protocol for destruction of poliovirus infectious materials. CONCLUSION: This study has revealed the successful containment of all poliovirus infectious materials in the laboratories surveyed. It has also revealed some surveillance gaps. We recommend that the surveillance system be improved to maintain the gains from the containment exercise and avoid reintroduction of infectious materials into biomedical facilities. This reduces the chances of viral reintroduction to the population in general.

Modeling Poliovirus Transmission in Pakistan and Afghanistan to Inform Vaccination Strategies in Undervaccinated Subpopulations.

Due to security, access, and programmatic challenges in areas of Pakistan and Afghanistan, both countries continue to sustain indigenous wild poliovirus (WPV) transmission and threaten the success of global polio eradication and oral poliovirus vaccine (OPV) cessation. We fitted an existing differential-equation-based poliovirus transmission and OPV evolution model to Pakistan and Afghanistan using four subpopulations to characterize the well-vaccinated and undervaccinated subpopulations in each country. We explored retrospective and prospective scenarios for using inactivated poliovirus vaccine (IPV) in routine immunization or supplemental immunization activities (SIAs). The undervaccinated subpopulations sustain the circulation of serotype 1 WPV and serotype 2 circulating vaccine-derived poliovirus. We find a moderate impact of past IPV use on polio incidence and population immunity to transmission mainly due to (1) the boosting effect of IPV for individuals with preexisting immunity from a live poliovirus infection and (2) the effect of IPV-only on oropharyngeal transmission for individuals without preexisting immunity from a live poliovirus infection. Future IPV use may similarly yield moderate benefits, particularly if access to undervaccinated subpopulations dramatically improves. However, OPV provides a much greater impact on transmission and the incremental benefit of IPV in addition to OPV remains limited. This study suggests that despite the moderate effect of using IPV in SIAs, using OPV in SIAs remains the most effective means to stop transmission, while limited IPV resources should prioritize IPV use in routine immunization.

Transition Planning For After Polio Eradication.

The Global Polio Eradication Initiative (GPEI) has been in operation since 1988, now spends $1 billion annually, and operates through thousands of staff and millions of volunteers in dozens of countries. It has brought polio to the brink of eradication. After eradication is achieved, what should happen to the substantial assets, capabilities, and lessons of the GPEI? To answer this question, an extensive process of transition planning is underway. There is an absolute need to maintain and mainstream some of the functions, to keep the world polio-free. There is also considerable risk-and, if seized, substantial opportunity-for other health programs and priorities. And critical lessons have been learned that can be used to address other health priorities. Planning has started in the 16 countries where GPEI's footprint is the greatest and in the program's 5 core agencies. Even though poliovirus transmission has not yet been stopped globally, this planning process is gaining momentum, and some plans are taking early shape. This is a complex area of work-with difficult technical, financial, and political elements. There is no significant precedent. There is forward motion and a willingness on many sides to understand and address the risks and to explore the opportunities. Very substantial investments have been made, over 30 years, to eradicate a human pathogen from the world for the second time ever. Transition planning represents a serious intent to responsibly bring the world's largest global health effort to a close and to protect and build upon the investment in this effort, where appropriate, to benefit other national and global priorities. Further detailed technical work is now needed, supported by broad and engaged debate, for this undertaking to achieve its full potential.

Routine Immunization Service Delivery Through the Basic Package of Health Services Program in Afghanistan: Gaps, Challenges, and Opportunities.

Background: The Basic Package of Health Services (BPHS) program has increased access to immunization services for children living in rural Afghanistan. However, multiple surveys have indicated persistent immunization coverage gaps. Hence, to identify gaps in implementation, an assessment of the BPHS program was undertaken, with specific focus on the routine immunization (RI) component. Methods: A cross-sectional survey was conducted in 2014 on a representative sample drawn from a sampling frame of 1858 BPHS health facilities. Basic descriptive analysis was performed, capturing general characteristics of survey respondents and assessing specific RI components, and χ2 tests were used to evaluate possible differences in service delivery by type of health facility. Results: Of 447 survey respondents, 27% were health subcenters (HSCs), 30% were basic health centers, 32% were comprehensive health centers, and 12% were district hospitals. Eighty-seven percent of all respondents offered RI services, though only 61% of HSCs did so. Compared with other facility types, HSCs were less likely to have adequate stock of vaccines, essential cold-chain equipment, or proper documentation of vaccination activities. Conclusions: There is an urgent need to address manpower and infrastructural deficits in RI service delivery through the BPHS program, especially at the HSC level.