2022 Polio outbreak, Rockland County, NY: Cost evaluation of strategies to prevent future outbreaks of vaccine-preventable diseases.

In 1994, the World Health Organization Region of the Americas was declared polio-free. In July 2022, a confirmed case of paralytic polio in an unvaccinated adult resident of Rockland County, New York was reported by the New York State Department of Health (NYSDOH) and Rockland County Department of Health (RCDOH). While only one case was identified, a single case of paralytic polio represents a public health emergency in the United States. The patient's county of residence was identified to have low vaccination coverage indicating that the community was at risk for additional cases. Disease outbreaks are resource-intensive and incur high costs to the patient, local health departments, and to society. These costs are potentially avoidable for vaccine-preventable diseases and thus, highlight the urgency to not only interrupt transmission but to prevent future vaccine-preventable disease outbreaks by improving vaccination coverage. Following case confirmation, an investigation and response was initiated by NYSDOH, along with local health departments and the Centers for Disease Control and Prevention (CDC). After the initial investigation and response, collaborative efforts to mitigate risk and strengthen routine immunization continued, which included provider outreach and immunization record assessments of Head Start and licensed childcare facilities (primarily those with missing or incomplete required vaccination coverage reports from the previous year) in Rockland County. We estimated the costs of (1) provider outreach and (2) childcare and pre-kindergarten immunization record assessments of select licensed childcare and Head Start facilities in Rockland County. The total labor cost incurred for these activities was $138,514 with a total of 2,555 h incurred. Often there are unique opportunities in the midst of an outbreak for public health to implement activities to proactively address low vaccination and strengthen vaccination coverage and possibly prevent future outbreaks. Understanding the cost of these activities might help inform future outbreak planning.

Health Economic Analysis of Antiviral Drugs in the Global Polio Eradication Endgame.

BACKGROUND: Polio antiviral drugs (PAVDs) may provide a critical tool in the eradication endgame by stopping poliovirus infections in immunodeficient individuals who may not clear the virus without therapeutic intervention. Although prolonged/chronic poliovirus excreters are rare, they represent a source of poliovirus reintroduction into the general population. Prior studies that assumed the successful cessation of all oral poliovirus vaccine (OPV) use estimated the potential upper bound of the incremental net benefits (INBs) of resource investments in research and development of PAVDs. However, delays in polio eradication, OPV cessation, and the development of PAVDs necessitate an updated economic analysis to reevaluate the costs and benefits of further investments in PAVDs. METHODS: Using a global integrated model of polio transmission, immunity, vaccine dynamics, risks, and economics, we explore the risks of reintroduction of polio transmission due to immunodeficiency-related vaccine-derived poliovirus (iVDPV) excreters and reevaluate the upper bound of the INBs of PAVDs. RESULTS: Under the current conditions, for which the use of OPV will likely continue for the foreseeable future, even with successful eradication of type 1 wild poliovirus by the end of 2023 and continued use of Sabin OPV for outbreak response, we estimate an upper bound INB of 60 million US$2019. With >100 million US$2019 already invested in PAVD development and with the introduction of novel OPVs that are less likely to revert to neurovirulence, our analysis suggests the expected INBs of PAVDs would not offset their costs. CONCLUSIONS: While PAVDs could play an important role in the polio endgame, their expected economic benefits drop with ongoing OPV use and poliovirus transmissions. However, stakeholders may pursue the development of PAVDs as a desired product regardless of their economic benefits.HighlightsWhile polio antiviral drugs could play an important role in the polio endgame, their expected economic benefits continue to drop with delays in polio eradication and the continued use of oral poliovirus vaccines.The incremental net benefits of investments in polio antiviral drug development and screening for immunodeficiency-related circulating polioviruses are small.Limited global resources are better spent on increasing global population immunity to polioviruses to stop and prevent poliovirus transmission.

Poliovirus outbreak in New York State, August 2022: qualitative assessment of immediate public health responses and priorities for improving vaccine coverage.

In 2022, a case of paralysis was reported in an unvaccinated adult in Rockland County (RC), New York. Genetically linked detections of vaccine-derived poliovirus type 2 (VDPV2) were reported in multiple New York counties, England, Israel, and Canada. The aims of this qualitative study were to: i) review immediate public health responses in New York to assess the challenges in addressing gaps in vaccination coverage; ii) inform a longer-term strategy to improving vaccination coverage in under-vaccinated communities, and iii) collect data to support comparative evaluations of transnational poliovirus outbreaks. Twenty-three semi-structured interviews were conducted with public health professionals, healthcare professionals, and community partners. Results indicate that i) addressing suboptimal vaccination coverage in RC remains a significant challenge after recent disease outbreaks; ii) the poliovirus outbreak was not unexpected and effort should be invested to engage mothers, the key decision-makers on childhood vaccination; iii) healthcare providers (especially paediatricians) received technical support during the outbreak, and may require resources and guidance to effectively contribute to longer-term vaccine engagement strategies; vi) data systems strengthening is required to help track under-vaccinated children. Public health departments should prioritize long-term investments in appropriate communication strategies, countering misinformation, and promoting the importance of the routine immunization schedule.

Responding to Africa's burden of disease: accelerating progress.

Although Africa is home to about 14% of the global population (1.14 billion people), it is growing three times faster than the global average [1]. The continent carries a high burden of disease, but there has been real progress in eradication, elimination, and control since 2015. Examples are the eradication of wild polio in 2020 [2] and the eradication or elimination of neglected tropical diseases, such as dracunculiasis in Kenya in 2018; Human African trypanosomiasis in Togo in 2022; and trachoma in Togo, Gambia, Ghana, and Malawi in 2022 [3]. New HIV infections reduced by 44% in 2021 compared to 2010 [4], and in 2021 the African region passed the 2020 milestone of the End TB Strategy, with a 22% reduction in new infections compared with 2015 [5].

Co-administration of Oral Cholera Vaccine With Oral Polio Vaccine Among Bangladeshi Young Children: A Randomized Controlled Open Label Trial to Assess Interference.

BACKGROUND: Cholera remains a public health threat for low- and middle-income countries, particularly in Asia and Africa. Shanchol™, an inactivated oral cholera vaccine (OCV) is currently in use globally. OCV and oral poliovirus vaccines (OPV) could be administered concomitantly, but the immunogenicity and safety of coadministration among children aged 1-3 years is unknown. METHODS: We undertook an open-label, randomized, controlled, inequality trial in Dhaka city, Bangladesh. Healthy children aged 1-3 years were randomly assigned to 1 of 3 groups: bivalent OPV (bOPV)-alone, OCV-alone, or combined bOPV + OCV and received vaccines on the day of enrollment and 28 days later. Blood samples were collected on the day of enrollment, day 28, and day 56. Serum poliovirus neutralizing antibodies and vibriocidal antibodies against Vibrio cholerae O1 were assessed using microneutralization assays. RESULTS: A total of 579 children aged 1‒3 years were recruited, 193 children per group. More than 90% of the children completed visits at day 56. Few adverse events following immunization were recorded and were equivalent among study arms. On day 28, 60% (90% confidence interval: 53%-67%) and 54% (46%-61%) of participants with co-administration of bOPV + OCV responded to polioviruses type 1 and 3, respectively, compared to 55% (47%-62%) and 46% (38%-53%) in the bOPV-only group. Additionally, >50% of participants showed a ≥4-fold increase in vibriocidal antibody titer responses on day 28, comparable to the responses observed in OCV-only arm. CONCLUSIONS: Co-administration of bOPV and OCV is safe and effective in children aged 1-3 years and can be cost-beneficial. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT03581734).

Assessment of open data kit mobile technology adoption to enhance reporting of supportive supervision conducted for oral poliovirus vaccine supplementary immunization activities in Nigeria, March 2017-February 2020.

Introduction: in Nigeria, supportive supervision of Supplementary Immunization Activities (SIA) is a quality improvement strategy for providing support to vaccination teams administering the poliovirus vaccines to children under 5 years of age. Supervision activities were initially reported in paper forms. This had significant limitations, which led to Open Data Kit (ODK) technology being adopted in March 2017. A review was conducted to assess the impact of ODK for supervision reporting in place of paper forms. Methods: issues with paper-based reporting and the benefits of ODK were recounted. We determined the average utilization of ODK per polio SIA rounds and assessed the supervision coverage over time based on the proportion of local government areas with ODK geolocation data per round. Results: a total of 17 problematic issues were identified with paper-based reporting, and ODK addressed all the issues. Open Data Kit-based supervision reports increased from 3,125 in March 2017 to 51,060 in February 2020. Average ODK submissions for national rounds increased from 84 in March 2017 to 459 in February 2020 and for sub-national rounds increased from 533 in July 2017 to 1,596 in October 2019. Supportive supervision coverage improved from 42.5% in March 2017 to 97% in February 2020. Conclusion: the use of digital technologies in public health has comparative advantages over paper forms, and the adoption of ODK for supervision reporting during polio SIAs in Nigeria experienced the advantages. The visibility and coverage of supportive supervision improved, consequentially contributing to the improved quality of polio SIAs.

Immunity to poliovirus in Afghanistan: A household sampling method for serological assessment based on geographical information systems.

Afghanistan continues to experience challenges affecting polio eradication. Mass polio vaccination campaigns, which aim to protect children under the age of 5, are a key eradication strategy. To date, the polio program in Afghanistan has only employed facility-based seroprevalence surveys, which can be subject to sampling bias. We describe the feasibility in implementing a cross-sectional household poliovirus seroprevalence survey based on geographical information systems (GIS) in three districts. Digital maps with randomly selected predetermined starting points were provided to teams, with a total target of 1,632 households. Teams were instructed to navigate to predetermined starting points and enrol the closest household within 60 m. To assess effectiveness of these methods, we calculated percentages for total households enrolled with valid geocoordinates collected within the designated boundary, and whether the Euclidean distance of households were within 60 m of a predetermined starting point. A normalized difference vegetation index (NDVI) image ratio was conducted to further investigate variability in team performances. The study enrolled a total of 78% of the target sample with 52% of all households within 60 m of a pre-selected point and 79% within the designated cluster boundary. Success varied considerably between the four target areas ranging from 42% enrolment of the target sample in one place to 90% enrolment of the target sample in another. Interviews with the field teams revealed that differences in security status and amount of non-residential land cover were key barriers to higher enrolment rates. Our findings indicate household poliovirus seroprevalence surveys using GIS-based sampling can be effectively implemented in polio endemic countries to capture representative samples. We also proposed ways to achieve higher success rates if these methods are to be used in the future, particularly in areas with concerns of insecurity or spatially dispersed residential units.

Current and next-generation formulation strategies for inactivated polio vaccines to lower costs, increase coverage, and facilitate polio eradication.

Implementation of inactivated polio vaccines (IPV) containing Sabin strains (sIPV) will further enable global polio eradication efforts by improving vaccine safety during use and containment during manufacturing. Moreover, sIPV-containing vaccines will lower costs and expand production capacity to facilitate more widespread use in low- and middle-income countries (LMICs). This review focuses on the role of vaccine formulation in these efforts including traditional Salk IPV vaccines and new sIPV-containing dosage forms. The physicochemical properties and stability profiles of poliovirus antigens are described. Formulation approaches to lower costs include developing multidose and combination vaccine formats as well as improving storage stability. Formulation strategies for dose-sparing and enhanced mucosal immunity include employing adjuvants (e.g. aluminum-salt and newer adjuvants) and/or novel delivery systems (e.g. ID administration with microneedle patches). The potential for applying these low-cost formulation development strategies to other vaccines to further improve vaccine access and coverage in LMICs is also discussed.

Assessment of serological responses following vaccination campaigns with type 2 novel oral polio vaccine: a population-based study in Tajikistan in 2021.

BACKGROUND: Novel oral poliovirus vaccine type 2 (nOPV2) was used to control an outbreak of type 2 circulating vaccine derived poliovirus (cVDPV2) in Tajikistan, in 2021. We measured seroconversion and seroprevalence of type 2 polio antibodies in children who were reported to have received two doses of nOPV2 in outbreak response campaigns. METHODS: In this community serosurvey, children born after Jan 1, 2016 were enrolled from seven districts in Tajikistan. Dried blood spot cards were collected before nOPV2 campaigns and after the first and second rounds of the campaigns and were sent to the Centers for Disease Control and Prevention (Atlanta, GA, USA) for microneutralisation assay to determine presence of polio antibodies. The primary endpoint was to assess change in seroprevalence and seroconversion against poliovirus serotype 2 after one and two doses of nOPV2. FINDINGS: 228 (97%) of 236 enrolled children were included in the analysis. The type 2 antibody seroprevalence was 26% (53/204; 95% CI 20 to 33) before nOPV2, 77% (161/210; 70 to 82) after one dose of nOPV2, and 83% (174/209; 77 to 88) after two doses of nOPV2. The increase in seroprevalence was statistically significant between baseline and after one nOPV2 dose (51 percentage points [42 to 59], p<0·0001), but not between the first and second doses (6 percentage points [-2 to 15], p=0·12). Seroconversion from the first nOPV2 dose, 67% (89/132; 59 to 75), was significantly greater than that from the second nOPV2 dose, 44% (20/45; 30 to 60; χ2 p=0·010). Total seroconversion after two nOPV2 doses was 77% (101/132; 68 to 83). INTERPRETATION: Our study demonstrated strong immune responses following nOPV2 outbreak response campaigns in Tajikistan. Our results support previous clinical trial data on the generation of poliovirus type 2 immunity by nOPV2 and provide evidence that nOPV2 can be appropriate for the cVDPV2 outbreak response. The licensure and WHO prequalification of nOPV2 should be accelerated to facilitate wider use of the vaccine. FUNDING: World Health Organization, Centers for Disease Control and Prevention, and Rotary International.

One vaccine to counter many diseases? Modeling the economics of oral polio vaccine against child mortality and COVID-19.

Introduction: Recent reviews summarize evidence that some vaccines have heterologous or non-specific effects (NSE), potentially offering protection against multiple pathogens. Numerous economic evaluations examine vaccines' pathogen-specific effects, but less than a handful focus on NSE. This paper addresses that gap by reporting economic evaluations of the NSE of oral polio vaccine (OPV) against under-five mortality and COVID-19. Materials and methods: We studied two settings: (1) reducing child mortality in a high-mortality setting (Guinea-Bissau) and (2) preventing COVID-19 in India. In the former, the intervention involves three annual campaigns in which children receive OPV incremental to routine immunization. In the latter, a susceptible-exposed-infectious-recovered model was developed to estimate the population benefits of two scenarios, in which OPV would be co-administered alongside COVID-19 vaccines. Incremental cost-effectiveness and benefit-cost ratios were modeled for ranges of intervention effectiveness estimates to supplement the headline numbers and account for heterogeneity and uncertainty. Results: For child mortality, headline cost-effectiveness was $650 per child death averted. For COVID-19, assuming OPV had 20% effectiveness, incremental cost per death averted was $23,000-65,000 if it were administered simultaneously with a COVID-19 vaccine <200 days into a wave of the epidemic. If the COVID-19 vaccine availability were delayed, the cost per averted death would decrease to $2600-6100. Estimated benefit-to-cost ratios vary but are consistently high. Discussion: Economic evaluation suggests the potential of OPV to efficiently reduce child mortality in high mortality environments. Likewise, within a broad range of assumed effect sizes, OPV (or another vaccine with NSE) could play an economically attractive role against COVID-19 in countries facing COVID-19 vaccine delays. Funding: The contribution by DTJ was supported through grants from Trond Mohn Foundation (BFS2019MT02) and Norad (RAF-18/0009) through the Bergen Center for Ethics and Priority Setting.

Cost-effectiveness of various immunization schedules with inactivated Sabin strain polio vaccine in Hangzhou, China.

Background: It is necessary to select suitable inactivated poliovirus vaccine(IPV) and live, attenuated oral poliovirus vaccine (OPV) sequential immunization programs and configure the corresponding health resources. An economic evaluation was conducted on the sequential procedures of Sabin strain-based IPV (sIPV) and bivalent OPV (bOPV) with different doses to verify whether a cost-effectiveness target can be achieved. This study aimed to evaluate the cost-effectiveness of different sIPV immunization schedules, which would provide convincing evidence to further change the poliovirus vaccine (PV) immunization strategies in China. Methods: Five strategies were included in this analysis. Based on Strategy 0(S0), the incremental cost (IC), incremental effect (IE), and incremental cost-effectiveness ratio (ICER) of the four different strategies (S1/S2/S3/S4) were calculated based on the perspective of the society. Seven cost items were included in this study. Results of field investigations and expert consultations were used to calculate these costs. Results: The ICs of S1/S2/S3/S4 was Chinese Yuan (CNY) 30.77, 68.58, 103.82, and 219.82 million, respectively. The IE of vaccine-associated paralytic poliomyelitis (IEVAPP) cases of S1/S2/S3/S4 were 0.22, 0.22, 0.22, and 0.11, respectively, while the IE of disability-adjusted life-years (IEDALY) of S1/S2/S3/S4 were 8.98, 8.98, 8.98, and 4.49, respectively. The ICERVAPP of S1/S2/S3/S4 gradually increased to CNY 13.99, 31.17, 47.19, and 199.83 million/VAPP, respectively. The ICERDALY of S1/S2/S3/S4 also gradually increased to CNY 0.34, 0.76, 1.16, and 4.90 million/DALY, respectively. Conclusion: ICERVAPP and ICERDALY were substantially higher for S3 (four-sIPV) and S4 (replacement of self-funded sIPV based on one-sIPV-three-bOPV). Two-sIPV-two-bOPV had a cost-effectiveness advantage, whereas S2/S3/S4 had no cost-effectiveness advantage.

Avaliação da cobertura vacinal da poliomielite nos estados da região sul, com foco no município de Pato Branco, entre os anos de 2009-2019 / Assessment of polio vaccination coverage in the southern states, focusing on the municipality of Pato Branco, from 2009-2019 / Evaluación de la cobertura de vacunación contra la poliomielitis en los estados de la región sur, con enfoque en el municipio de Pato Branco, entre los años 2009-2019

Objetivo: Analisar a taxa de cobertura vacinal da poliomielite em relação às metas de vacinação de 95% da população-alvo, estabelecidas pelo Ministério da Saúde, com base nos registros de imunização do DATASUS nos estados do Paraná, Santa Catarina e Rio Grande do Sul, que compõem a região sul do Brasil, e na cidade de Pato Branco, PR. Métodos: Estudo descritivo de abordagem quantitativa referente à cobertura vacinal da Poliomielite nos estados da região sul e no município de Pato Branco, PR com resultados da cobertura avaliados quanto ao alcance das metas estabelecidas pelo Ministério da Saúde e comparado o desempenho entre os estados e o município no período de 2009 a 2019. Os dados foram recolhidos da seção de Imunizações do DATASUS, o departamento de informática do Sistema Único de Saúde do Brasil. Resultados: No período analisado, o município de Pato Branco se manteve com uma taxa satisfatória em relação à meta estabelecida pelo Ministério da Saúde, exceto nos anos de 2017 e 2018, onde ficou abaixo da meta em cerca de 3% e 11%, respectivamente. Em relação aos estados do sul, o estado do Paraná mostrou-se abaixo da meta de cobertura vacinal recomendada na maioria dos anos estudados, com a menor cobertura ocorrendo em 2017, ficando 15% abaixo do esperado; o estado de Santa Catarina, apesar de apresentar queda desde o ano de 2014, apresentou os melhores índices de cobertura vacinal, com a maior taxa de queda de cobertura no ano de 2018 com cerca de 7%; e o estado do Rio Grande do Sul se apresentou como o estado com o pior desempenho na região, demonstrando quedas significativas da cobertura desde 2010, com menor taxa de vacinação em 2017, ficando 18% abaixo do esperado. Conclusões: Pode-se observar uma queda nos valores da cobertura vacinal entre os anos de 2009 a 2019, tanto no município de Pato Branco, PR, quanto nos estados do Paraná, Santa Catarina e Rio Grande do Sul, algo que é motivo de crescente preocupação pelos serviços de saúde do país devido à possibilidade de reintrodução da doença no território nacional. Ressalta-se, então, a necessidade de criação de estratégias eficazes para o combate das quedas das taxas de cobertura vacinal no país.

Objective: To analyze the rate of polio vaccination coverage in relation to the vaccination goals of 95% of the target population, set by the Ministry of Health, based on DATASUS immunization records in the states of Paraná, Santa Catarina, and Rio Grande do Sul, which make up the southern region of Brazil, and in the city of Pato Branco, PR. Methods: A descriptive study of quantitative approach regarding the vaccination coverage of Poliomyelitis in the states of the southern region and in the municipality of Pato Branco, PR with coverage results evaluated as to the achievement of the goals set by the Ministry of Health and compared performance between the states and the municipality in the period from 2009 to 2019. The data were collected from the Immunizations section of DATASUS, the computer department of the Brazilian Unified Health System. Results: In the period analyzed, the municipality of Pato Branco remained with a satisfactory rate in relation to the target set by the Ministry of Health, except in the years 2017 and 2018, where it was below the target by about 3% and 11%, respectively. Regarding the southern states, the state of Paraná showed below the recommended vaccine coverage target in most of the years studied, with the lowest coverage occurring in 2017, being 15% below expected; the state of Santa Catarina, despite showing a drop since the year 2014, showed the best rates of vaccine coverage, with the highest rate of drop in coverage in the year 2018 with about 7%; and the state of Rio Grande do Sul presented itself as the state with the worst performance in the region, showing significant drops in coverage since 2010, with the lowest rate of vaccination in 2017, being 18% below expectations. Conclusions: A drop in vaccination coverage values can be observed between the years 2009 and 2019, both in the municipality of Pato Branco, PR, and in the states of Paraná, Santa Catarina, and Rio Grande do Sul, something that is a cause of growing concern for the country's health services due to the possibility of reintroduction of the disease in the national territory. Therefore, the need to create effective strategies to combat the declines in vaccination coverage rates in the country is highlighted.

Objetivo: Analizar la tasa de cobertura de vacunación antipoliomielítica en relación con las metas de vacunación del 95% de la población objetivo, establecidas por el Ministerio de Salud, a partir de los registros de inmunización DATASUS en los estados de Paraná, Santa Catarina y Rio Grande do Sul, que conforman la región sur de Brasil, y en la ciudad de Pato Branco, PR. Métodos: Estudio descriptivo de abordaje cuantitativo referente a la cobertura vacunal de la Poliomielitis en los estados de la región sur y en el municipio de Pato Branco, PR con resultados de la cobertura evaluados en cuanto al alcance de las metas establecidas por el Ministerio de Salud y comparado el rendimiento entre los estados y el municipio en el período de 2009 a 2019. Los datos se recogieron de la sección de Inmunizaciones de DATASUS, el departamento de informática del Sistema Único de Salud de Brasil. Resultados: En el período analizado, el municipio de Pato Branco se mantuvo con una tasa satisfactoria en relación a la meta establecida por el Ministerio de Salud, excepto en los años 2017 y 2018, donde estuvo por debajo de la meta en cerca de 3% y 11%, respectivamente. En lo que respecta a los estados del sur, el estado de Paraná se mostró por debajo de la meta de cobertura vacunal recomendada en la mayoría de los años estudiados, siendo la cobertura más baja la que se produjo en el año 2017, estando un 15% por debajo de lo esperado; el estado de Santa Catarina, a pesar de mostrar una caída desde el año 2014, mostró los mejores índices de cobertura vacunal, siendo la mayor tasa de caída de la cobertura en el año 2018 con cerca de un 7%; y el estado de Río Grande do Sul se presentó como el estado con peor desempeño en la región, demostrando caídas significativas en la cobertura desde 2010, con la tasa de vacunación más baja en 2017, siendo un 18% por debajo de lo esperado. Conclusiones: Se observa una caída en los valores de las coberturas de vacunación entre los años 2009 y 2019, tanto en el municipio de Pato Branco, PR, como en los estados de Paraná, Santa Catarina y Rio Grande do Sul, algo que es motivo de creciente preocupación para los servicios de salud del país debido a la posibilidad de reintroducción de la enfermedad en el territorio nacional. Por lo tanto, se destaca la necesidad de crear estrategias eficaces para combatir el descenso de las tasas de cobertura de vacunación en el país.

Health economic analysis of vaccine options for the polio eradication endgame: 2022-2036.

BACKGROUND: Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool to explore the dynamics of ending all use of one or more poliovirus vaccines to simplify the polio eradication endgame. RESEARCH DESIGN AND METHODS: With global reported cases of poliomyelitis trending higher since 2016, we apply an integrated global model to simulate prospective vaccine policies and strategies for OPV-using countries starting with initial conditions that correspond to the epidemiological poliovirus transmission situation at the beginning of 2022. RESULTS: Abruptly ending all OPV use in 2023 and relying only on IPV to prevent paralysis with current routine immunization coverage would lead to expected reestablished endemic transmission of poliovirus types 1 and 2, and approximately 150,000 expected cases of poliomyelitis per year. Alternatively, if OPV-using countries restart trivalent OPV (tOPV) use for all immunization activities and end IPV use, the model shows the lowest anticipated annual polio cases and lowest costs. CONCLUSIONS: Poor global risk management and coordination of OPV cessation remain a critical failure mode for the polio endgame, and national and global decision makers face difficult choices due to multiple available polio vaccine options and immunization strategies.

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.

Immunochemical and biophysical characterization of inactivated Sabin poliovirus products: Insights into rapid quality assessment tools.

The aim of this study was to demonstrate the strength of combining immunochemical and biophysical analysis tools for assessing the quality of Sabin inactivated poliovirus vaccine (Sabin-IPV) bulk products. We assessed Sabin-IPV serotypes 1, 2 and 3 from six different manufacturers and evaluated their comparability through biosensor analysis and biophysical characterization methods, including tryptophan fluorescence and asymmetrical flow field-flow fractionation - multi-angle light scattering analysis. These methods enabled us to assess antigenic as well as conformational and structural integrity profiles, respectively. Based on Sabin-IPV samples that were subjected to accelerated storage conditions, we revealed that existing immunochemical methods exhibit remarkably similar trends to the results obtained by the biophysical characterization methods. While the results underpin that the comparability of Sabin-IPV bulk products of different manufacturers is weak, information about their quality can rapidly be obtained by using both immunochemical and biophysical methods. Furthermore, the study highlights that quality assessment of Sabin-IPV can be obtained through biophysical techniques can complement the assessments performed with monoclonal antibodies and suggests that similar techniques could be employed to characterize other enteroviruses.

A novel semi-quantitative methodology for national poliovirus reintroduction and outbreak risk assessment.

BACKGROUND: Under the International Health Regulations (2005), World Health Organization Member States need to verify certification of polio-free status annually. In 2018, Australia sought to reassess and comprehensively characterise the risk posed by wild-type and vaccine-derived poliovirus introductions to national health security. However formal guidelines for national polio risk assessment were not publicly available. METHODS: Four risk elements were identified and weighted using an expert-informed modified Delphi method: reintroduction hazard; population susceptibility; detection capability; and response capability. Australian data and qualitative evidence were analysed, documented and scored against risk element indicators to characterise polio risk as a semi-quantitative estimate and qualitative risk category statement. RESULTS: The semi-quantitative risk characterisation calculated likelihood and impact scores of 0.43 and 0.13, respectively (possible range: 0.02-4.5). The assessment concluded that the risk of poliovirus reintroduction, resultant outbreaks of poliovirus infection, and sustained transmission occurring in Australia is very low. CONCLUSIONS: Until poliovirus is eradicated, it remains in countries' strategic health security interest to maintain optimal investment in polio prevention, preparedness, surveillance and response capability to manage their level of risk. We present a structured, transparent and reproducible methodology for national or sub-national polio risk characterisation that generates evidence for targeted investment to maintain polio-free status.

Environmental Surveillance for Risk Assessment in the Context of a Phase 2 Clinical Trial of Type 2 Novel Oral Polio Vaccine in Panama.

Environmental surveillance was recommended for risk mitigation in a novel oral polio vaccine-2 (nOPV2) clinical trial (M5-ABMG) to monitor excretion, potential circulation, and loss of attenuation of the two nOPV2 candidates. The nOPV2 candidates were developed to address the risk of poliovirus (PV) type 2 circulating vaccine-derived poliovirus (cVDPV) as part of the global eradication strategy. Between November 2018 and January 2020, an environmental surveillance study for the clinical trial was conducted in parallel to the M5-ABMG clinical trial at five locations in Panama. The collection sites were located upstream from local treatment plant inlets, to capture the excreta from trial participants and their community. Laboratory analyses of 49 environmental samples were conducted using the two-phase separation method. Novel OPV2 strains were not detected in sewage samples collected during the study period. However, six samples were positive for Sabin-like type 3 PV, two samples were positive for Sabin-like type 1 PV, and non-polio enteroviruses NPEVs were detected in 27 samples. One of the nOPV2 candidates has been granted Emergency Use Listing by the World Health Organization and initial use started in March 2021. This environmental surveillance study provided valuable risk mitigation information to support the Emergency Use Listing application.

Assessing community engagement in Nigeria polio eradication initiative: application of the Consolidated Framework for Implementation Research.

OBJECTIVE: This study employed the Consolidated Framework for Implementation Research (CFIR) to assess factors that enhanced or impeded the implementation of community engagement strategies using the Nigerian polio programme as a point of reference. DESIGN: This study was a part of a larger descriptive cross-sectional survey. The CFIR was used to design the instrument which was administered through face-to-face and phone interviews as well as a web-based data collection platform, Qualtrics. SETTING: The study took place in at least one State from each of the six geopolitical zones in Nigeria (Nasarawa, Borno, Kano, Sokoto, Anambra, Bayelsa, Lagos, Ondo and Oyo States as well as the Federal Capital Territory). PARTICIPANTS: The respondents included programme managers, policy-makers, researchers and frontline field implementers affiliated with the Global Polio Eradication Initiative (PEI) core partner organisations, the three tiers of the government health parastatals (local, state and federal levels) and academic/research institutions. RESULTS: Data for this study were obtained from 364 respondents who reported participation in community engagement activities in Nigeria's PEI. Majority (68.4%) had less than 10 years' experience in PEI, 57.4% were involved at the local government level and 46.9% were team supervisors. Almost half (45.0%) of the participants identified the process of conducting the PEI program and social environment (56.0%) as the most important internal and external contributor to implementing community engagement activities in the community, respectively. The economic environment (35.7%) was the most frequently reported challenge among the external challenges to implementing community engagement activities. CONCLUSION: Community engagement strategies were largely affected by the factors relating to the process of conducting the polio programme, the economic environment and the social context. Therefore, community engagement implementers should focus on these key areas and channel resources to reduce obstacles to achieve community engagement goals.