Erradicación de la poliomielitis en España: ¿qué ha pasado en la última década? / Eradication of poliomyelitis in Spain: What has happened in the last decade?

Al cumplirse sesenta años desde el inicio de la campaña de vacunación frente a la poliomielitis en España, se destaca el importante hito en el control de la enfermedad que ha supuesto el cambio desde una incidencia de más de 2.000 casos anuales en la década de los 60 a una ausencia mantenida de poliovirus (PV) salvaje desde 1988. A pesar del impacto negativo observado en las coberturas de vacunación de poliomielitis al inicio de la pandemia de COVID-19, estas se fueron recuperando, alcanzando un 98,2% en la primovacunación en 2022. En la última década, se han identificado dos elementos esenciales para mantener el objetivo de eliminación de la poliomielitis y que, además, refuerzan la importancia de mantener altas coberturas de vacunación: los sistemas de vigilancia epidemiológica robustos y la respuesta rápida a las alertas para proteger a la población vulnerable y evitar la circulación del virus. Es crucial interrumpir la transmisión a nivel internacional para lograr la erradicación, manteniendo una vigilancia continua de alta calidad y una coordinación efectiva entre los diferentes niveles frente a cualquier detección de PV, ya sea salvaje o derivado de la vacuna.(AU)

On the 60th anniversary of the initiation of the polio vaccination campaign in Spain, the significant milestone in achieving disease control is highlighted. There has been a shift from an incidence of over 2,000 yearly cases in the 1960s to a sustained absence of wild poliovirus (WPV) since 1988. Despite the observed negative impact on polio vaccination coverage at the onset of the COVID-19 pan-demic, these rates gradually recovered, reaching 98.2% in primary vaccination in 2022. Over the past decade, two essential elements have been identified to maintain the goal of polio elimination and that reinforces the importance of sustaining high vaccination co-verage: robust epidemiological surveillance systems and a swift response to alerts to protect the vulnerable population and prevent virus reintroduction. In order to achieve eradication, it is crucial to interrupt international transmission and maintain continuous high-quality surveillance and effective coordination across different levels in response to any detection of PV, wild or vaccine derived.This article aimed to provide a comprehensive view of the polio eradication situation in Spain, focusing on the key events that occu-rred in the last decade and the present and future challenges.(AU)

[Eradication of poliomyelitis in Spain: What has happened in the last decade?] / Erradicación de la poliomielitis en España: ¿qué ha pasado en la última década?

On the 60th anniversary of the initiation of the polio vaccination campaign in Spain, the significant milestone in achieving disease control is highlighted. There has been a shift from an incidence of over 2,000 yearly cases in the 1960s to a sustained absence of wild poliovirus (WPV) since 1988. Despite the observed negative impact on polio vaccination coverage at the onset of the COVID-19 pandemic, these rates gradually recovered, reaching 98.2% in primary vaccination in 2022. Over the past decade, two essential elements have been identified to maintain the goal of polio elimination and that reinforces the importance of sustaining high vaccination coverage: robust epidemiological surveillance systems and a swift response to alerts to protect the vulnerable population and prevent virus reintroduction. In order to achieve eradication, it is crucial to interrupt international transmission and maintain continuous high-quality surveillance and effective coordination across different levels in response to any detection of PV, wild or vaccine derived. This article aimed to provide a comprehensive view of the polio eradication situation in Spain, focusing on the key events that occurred in the last decade and the present and future challenges.

hito en el control de la enfermedad que ha supuesto el cambio desde una incidencia de más de 2.000 casos anuales en la década de los 60 a una ausencia mantenida de poliovirus (PV) salvaje desde 1988. A pesar del impacto negativo observado en las coberturas de vacunación de poliomielitis al inicio de la pandemia de la COVID-19, estas se fueron recuperando, alcanzando un 98,2% en la primovacunación en 2022. En la última década se han identificado dos elementos esenciales para mantener el objetivo de eliminación de la poliomielitis y que, además, refuerzan la importancia de mantener altas coberturas de vacunación: los sistemas de vigilancia epidemiológica robustos y la respuesta rápida a las alertas para proteger a la población vulnerable y evitar la circulación del virus. Es crucial interrumpir la transmisión a nivel internacional para lograr la erradicación, manteniendo una vigilancia continua de alta calidad y una coordinación efectiva entre los diferentes niveles frente a cualquier detección de PV, ya sea salvaje o derivado de la vacuna. Este artículo tuvo como objetivo proporcionar una visión integral sobre la situación de erradicación de la poliomielitis en España, centrándose en los eventos clave ocurridos en la última década y en los retos presentes y futuros.

Vitamin D Supplementation and Prior Oral Poliovirus Vaccination Decrease Odds of COVID-19 Outcomes among Adults Recently Inoculated with Inactivated Poliovirus Vaccine.

BACKGROUND: Structural and functional commonalities between poliovirus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) suggest that poliovirus inoculation may induce antibodies that mitigate the coronavirus disease (COVID-19). No known studies have evaluated COVID-19 risk factors in adults recently vaccinated against poliovirus. STUDY OBJECTIVE: Among adults with no history of COVID-19 infection or vaccination, who recently received an inactivated poliovirus vaccine (IPV), we sought to determine which biological factors and social determinants of health (SDOH) may be associated with (1) testing positive for SARS-CoV-2, (2) experiencing COVID-19 symptoms, and (3) a longer duration of COVID-19 symptoms. METHODS: The influence of biological factors and SDOH on SARS-CoV-2 infection and COVID-19 symptoms were evaluated among 282 adults recently inoculated with IPV. Participant-reported surveys were analyzed over 12 months post-enrollment. Bivariate and multivariate linear and logistic regression models identified associations between variables and COVID-19 outcomes. RESULTS: Adjusting for COVID-19 vaccinations, variants, and other SDOH, secondary analyses revealed that underlying conditions, employment, vitamin D, education, and the oral poliovirus vaccination (OPV) were associated with COVID-19 outcomes. The odds of testing positive for SARS-CoV-2 and experiencing symptoms were significantly reduced among participants who took vitamin D (OR 0.12 and OR 0.09, respectively). Unemployed or part-time working participants were 72% less likely to test positive compared with full-time workers. No prior dose of OPV was one of the strongest predictors of SARS-CoV-2 infection (OR 4.36) and COVID-19 symptoms (OR 6.95). CONCLUSIONS: Findings suggest that prophylactic measures and mucosal immunity may mitigate the risk and severity of COVID-19 outcomes. Larger-scale studies may inform future policies.

The role of a genetically stable, novel oral type 2 poliovirus vaccine in the poliomyelitis endgame.

Poliovirus infection causes paralysis in up to 1 in 200 infected persons. The use of safe and effective inactivated poliovirus vaccines and live attenuated oral poliovirus vaccines (OPVs) means that only two pockets of wild-type poliovirus type 1 remain, in Afghanistan and Pakistan. However, OPVs can revert to virulence, causing outbreaks of circulating vaccine-derived poliovirus (cVDPV). During 2020-2022, cVDPV type 2 (cVDPV2) was responsible for 97-99% of poliomyelitis cases, mainly in Africa. Between January and August 2022, cVDPV2 was detected in sewage samples in Israel, the United Kingdom and the United States of America, where a case of acute flaccid paralysis caused by cVDPV2 also occurred. The Pan American Health Organization has warned that Brazil, the Dominican Republic, Haiti and Peru are at very high risk for the reintroduction of poliovirus and an additional eight countries in Latin America are at high risk, following dropping vaccination rates (average 80% coverage in 2022). Sabin type 2 monovalent OPV has been used to control VDPV2 outbreaks, but its use could also lead to outbreaks. To address this issue, a more genetically stable, novel OPV2 (nOPV2) was developed against cVDPV2 and in 2020 was granted World Health Organization Emergency Use Listing. Rolling out a novel vaccine under the Emergency Use Listing in mass settings to contain outbreaks requires unique local regulatory and operational preparedness.

La infección por poliovirus ocasiona parálisis en hasta 1 de cada 200 personas infectadas. La utilización de vacunas con poliovirus inactivados y de vacunas antipoliomielíticas orales con poliovirus vivos atenuados (OPV) seguras y eficaces ha logrado que solo queden dos focos de poliovirus salvaje de tipo 1, en Afganistán y Pakistán. Sin embargo, las vacunas con OPV pueden revertir a la virulencia y producir brotes de poliovirus circulantes de origen vacunal (cVDPV). Durante el período 2020-2022, el cVDPV de tipo 2 (cVDPV2) fue la causa del 97-99% de los casos de poliomielitis, sobre todo en África. Entre enero y agosto del 2022, se encontró el cVDPV2 en muestras de aguas residuales en Estados Unidos de América, donde se produjo un caso de parálisis flácida aguda por el cVDPV2, Israel y Reino Unido y. La Organización Panamericana de la Salud ha advertido que, tras la caída de las tasas de vacunación (con una cobertura promedio del 80% en el 2022), Brasil, Haití, Perú y República Dominicana corren un riesgo muy alto de reintroducción del poliovirus, en tanto que otros ocho países de América Latina se encuentran en una situación de alto riesgo. La OPV monovalente de tipo 2 de Sabin se ha utilizado para controlar los brotes de VDPV2, pero su empleo también podría ocasionar brotes. Para hacer frente a este problema, se creó una nueva OPV2 (nOPV2) contra el cVDPV2, genéticamente más estable, que en el 2020 se incluyó en la lista de uso en emergencias de la Organización Mundial de la Salud. El despliegue a gran escala de una nueva vacuna incluida en la lista de uso en emergencias con el fin de contener los brotes exige una extraordinaria preparación regulatoria y operativa local.

A infecção pelo poliovírus causa paralisia em 1 de cada 200 pessoas infectadas. O uso de vacinas seguras e eficazes, tanto vacinas inativadas contra o poliovírus quanto vacinas orais contendo poliovírus atenuado (VOP), significa que restam apenas dois bolsões de poliovírus selvagem tipo 1, um no Afeganistão e outro no Paquistão. No entanto, a VOP pode reverter à virulência, causando surtos de poliovírus circulante derivado de vacina (cPVDV). No período 2020-2022, o cPVDV tipo 2 (cPVDV2) foi responsável por 97% a 99% dos casos de poliomielite, principalmente na África. Entre janeiro e agosto de 2022, o cPVDV2 foi detectado em amostras de esgoto em Israel, no Reino Unido e nos Estados Unidos da América, onde também houve um caso de paralisia flácida aguda causada pelo cPVDV2. A Organização Pan-Americana da Saúde alertou que, devido à queda nas taxas de vacinação (cobertura média de 80% em 2022), o Brasil, o Haiti, o Peru e a República Dominicana correm um risco muito alto de reintrodução do poliovírus e outros oito países da América Latina correm um risco alto. A VOP monovalente Sabin tipo 2 tem sido usada para controlar surtos de PVDV2, mas seu uso também pode levar a surtos. Para resolver esse problema, foi desenvolvida uma nova VOP2 (nVOP2), mais estável geneticamente, para combater o cPVDV2. Em 2020, a nVOP2 entrou na Lista de Uso Emergencial da Organização Mundial da Saúde. A distribuição de uma nova vacina incluída na Lista de Uso Emergencial em contextos de massa para conter surtos requer medidas originais de preparação operacional e regulatória em âmbito local.

Temporal and spatial distribution trends of polio vaccine coverage in less than one-year old children in Brazil, 2011-2021.

BACKGROUND: Low polio vaccine coverage can result in the spread of Poliovirus to areas free from viral circulation. This study analyzed the temporal trends and spatial distribution of polio vaccine coverage in one year-old children in Brazil, between 2011 and 2021. METHODS: This was an ecological, time-series study (2011 to 2021) with annual vaccine coverages against poliomyelitis, extracted from the Information System of the National Immunization Program from the 26 States and the Distrito Federal (DF). The percentage reductions in vaccination coverage in Brazil and in the Regions were calculated. Prais-Winsten regression models were used to analyze time series for the Regions and States, and spatial analysis identified the distribution of clusters (high-high; low-low; high-low and low-high) of vaccination coverages across Brazilian municipalities, using a 5% significance level. RESULTS: From 2011 to 2021, the coverage of polio vaccines decreased by 29,9%. There was a progressive increase observed in clusters resulting in low vaccination coverages (140 low-low Brazilian municipalities in 2011 vs. 403 in 2021), mostly reported in the North and Northeast regions of the country. There was a downward trend in vaccination coverages in 24 of the 26 States and DF (p ≤ 0.05). CONCLUSIONS: The reduction in polio vaccine coverage, as observed in the North and Northeast regions of Brazil, may favor the spread of Poliovirus. Therefore, vaccination strategies should be prioritized for children residing in areas with sharp and recurrent declines in vaccination coverages, including travelers, migrants, and refugees.

Effect of maternal immunisation with multivalent vaccines containing inactivated poliovirus vaccine (IPV) on infant IPV immune response: A phase 4, multi-centre randomised trial.

Multivalent diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccine (DTaP/IPV) has been offered to pregnant women in the United Kingdom since 2012. To assess the impact of maternal DTaP/IPV immunisation on the infant immune response to IPV, we measured poliovirus-specific neutralising antibodies at 2, 5 and 13 months of age in a randomised, phase 4 study of Repevax or Boostrix/IPV in pregnancy and in a non-randomised group born to women not given DTaP/IPV in pregnancy. Infants whose mothers received DTaP/IPV were less likely to seroconvert after three IPV doses than those whose mothers did not receive DTaP/IPV. At 13 months of age, 63/110 (57.2 %), 46/108 (42.6 %) and 40/108 (37.0 %) were seropositive to types 1 to 3, compared with 20/22 (90.9 %), 20/22 (90.9 %) and 14/20 (70.0 %) (p-values 0.003, <0.001 and 0.012). UK infants whose mothers are given DTaP/IPV in pregnancy may be insufficiently protected against poliomyelitis until their pre-school booster.

Mobile Money and the importance of timely, complete payments to frontline health campaign workers in the fight to eradicate polio: pilot experience from a World Health Organization digital payment platform in Africa.

BACKGROUND: In response to the increase in vaccine-derived poliovirus type 2 in Côte d'Ivoire, Mali, and many other African countries from 2017 to 2019, concentrated efforts are needed to improve the effectiveness of vaccination campaigns. Frontline polio health campaign worker engagement and job retention are critical to successful campaign implementation, as well as timely, in-full payment to these workers via an electronic system. METHODS: The Global Polio Eradication Initiative and its partners designed a road map to implement the World Health Organization Mobile Money digital payment system for health campaign workers across designated African Region countries and country-specific areas. The road map included: (1) strategy communication about Mobile Money to key stakeholders; (2) prioritization of Mobile Money pilot countries; (3) establishment of a digital finance team to support Mobile Money rollout for polio campaigns; (4) implementation of Mobile Money in select pilot areas; and (5) documentation by the digital finance team of Mobile Money implementation across pilot areas. At the country-specific level, and as described in the first pilot campaign in Côte d'Ivoire, implementation of Mobile Money occurred in 3 phases: precampaign, campaign, and postcampaign. RESULTS: Mobile Money was piloted in Côte d'Ivoire, Democratic Republic of the Congo, Ghana, Mali, and Republic of the Congo. Although program reach varied by country, the percentages of payments successfully made via Mobile Money in pilot countries were high: In campaign round 1, 99% of campaign workers in 2 regions in Mali, and 99% of campaign workers in 5 districts in Ghana were paid successfully. In Cote d'Ivoire, Mobile Money was piloted in all 113 districts for campaign rounds 1, 2 and 3, and in 4 districts in Abidjan for campaign round 3. In rounds 1, 2 and 3, 99.6%, 99.6%, and 99.9% of payments to polio health campaign workers, respectively, were made successfully. CONCLUSION: Implementation of the Mobile Money pilot program, particularly across Côte d'Ivoire, demonstrates the value of an electronic payment system in addressing frontline polio health campaign worker need for timely, in-full payment. The World Health Organization-led Mobile Money pilot program can serve as a model for agencies committed to delivering greater efficiencies and improved health campaigns in resource-challenged settings.

Temporal and spatial distribution of polio vaccine coverage in Brazil between 1997 and 2021 / Distribuição temporal e espacial da cobertura vacinal contra poliomielite no Brasil entre 1997 e 2021

ABSTRACT Objective: To analyze the temporal and spatial distribution of polio vaccine coverage in Brazilian states. Methods: An ecological time series study was conducted using data from the National Immunization Program Information System. The analyzed period was from 1997 to 2021. Joinpoint software was used to calculate the annual percentage change and average annual percentage change through regressions. QGIS 3.10.7 software was used to construct thematic maps. GeoDa 1.20.0.10 software was used to estimate spatial autocorrelation using the Global Moran's Index and Local Moran's Index. Results: National vaccine coverage in 1997 was 89.27%, decreasing to 61.32% in 2021. The trend analysis indicated an average annual decrease of 1.5% in polio vaccine coverage in Brazil. Across the country, 17 states showed a statistically significant reduction in the average annual percentage change rate. The highest average reduction rates in vaccine coverage among Brazilian states were observed in Amapá (−3.7%; 95%CI −6.0; −1.4) and Pernambuco (−3.3%; 95%CI −4.0; −2.5). In the spatial analysis, in Moran Global, a positive autocorrelation was identified in the years 2012 to 2021 (p<0.02), with an index value of 0.361, which means that geographically close areas tended to have similar levels of vaccination coverage. Conclusion: There was significant heterogeneity in coverage among states and a strong decrease trend in vaccination rates, which could facilitate the circulation of the poliovirus and pose a threat to the susceptible population.

RESUMO Objetivo: Analisar a distribuição temporal e espacial da cobertura da vacina contra poliomielite nos estados brasileiros. Métodos: Estudo ecológico de séries temporais, cuja fonte de dados foi o Sistema de Informação do Programa Nacional de Imunizações. O período analisado foi de 1997 a 2021. Utilizou-se o software Joinpoint para calcular a variação percentual anual e variação percentual anual média por meio de regressões. Para construção de mapas temáticos foi utilizado o software QGis 3.10.7. Para estimar a autocorrelação espacial com o Índice de Moran Global e Índice de Moran Local foi utilizado o software GeoDa 1.20.0.10. Resultados: A cobertura vacinal nacional em 1997 foi de 89,27%, passando para 61,32% em 2021. A análise de tendência apontou o decréscimo médio de 1,5% ao ano na cobertura da vacina contra poliomielite no Brasil. Em todo o país, 17 estados apresentaram redução estatisticamente significativa na taxa de variação percentual anual média. As maiores taxas médias de redução da cobertura vacinal entre os estados brasileiros foram observadas no Amapá (−3,7%; IC95% −6,0; −1,4) e em Pernambuco (−3,3%; IC95% −4,0; −2,5). Na análise espacial, no Moran Global, foi identificada autocorrelação positiva nos anos de 2012 a 2021 (p<0,02), com valor de índice de 0,361, o que significa que as áreas geograficamente próximas tenderam a ter níveis semelhantes de cobertura vacinal. Conclusão: Evidenciou-se expressiva heterogeneidade na cobertura entre os estados e forte tendência de queda dos índices, o que pode propiciar a circulação do poliovírus e colocar sob ameaça a população susceptível.

The role of a genetically stable, novel oral type 2 poliovirus vaccine in the poliomyelitis endgame / Utilidad de una nueva vacuna antipoliomielítica oral del serotipo 2 genéticamente estable contra el poliovirus de tipo 2 en la erradicación de la poliomielitis / O papel de uma nova vacina oral contra o poliovírus tipo 2, geneticamente estável, no estágio final da eliminação da poliomielite

ABSTRACT Poliovirus infection causes paralysis in up to 1 in 200 infected persons. The use of safe and effective inactivated poliovirus vaccines and live attenuated oral poliovirus vaccines (OPVs) means that only two pockets of wild-type poliovirus type 1 remain, in Afghanistan and Pakistan. However, OPVs can revert to virulence, causing outbreaks of circulating vaccine-derived poliovirus (cVDPV). During 2020-2022, cVDPV type 2 (cVDPV2) was responsible for 97-99% of poliomyelitis cases, mainly in Africa. Between January and August 2022, cVDPV2 was detected in sewage samples in Israel, the United Kingdom and the United States of America, where a case of acute flaccid paralysis caused by cVDPV2 also occurred. The Pan American Health Organization has warned that Brazil, the Dominican Republic, Haiti and Peru are at very high risk for the reintroduction of poliovirus and an additional eight countries in Latin America are at high risk, following dropping vaccination rates (average 80% coverage in 2022). Sabin type 2 monovalent OPV has been used to control VDPV2 outbreaks, but its use could also lead to outbreaks. To address this issue, a more genetically stable, novel OPV2 (nOPV2) was developed against cVDPV2 and in 2020 was granted World Health Organization Emergency Use Listing. Rolling out a novel vaccine under the Emergency Use Listing in mass settings to contain outbreaks requires unique local regulatory and operational preparedness.

RESUMEN La infección por poliovirus ocasiona parálisis en hasta 1 de cada 200 personas infectadas. La utilización de vacunas con poliovirus inactivados y de vacunas antipoliomielíticas orales con poliovirus vivos atenuados (OPV) seguras y eficaces ha logrado que solo queden dos focos de poliovirus salvaje de tipo 1, en Afganistán y Pakistán. Sin embargo, las vacunas con OPV pueden revertir a la virulencia y producir brotes de poliovirus circulantes de origen vacunal (cVDPV). Durante el período 2020-2022, el cVDPV de tipo 2 (cVDPV2) fue la causa del 97-99% de los casos de poliomielitis, sobre todo en África. Entre enero y agosto del 2022, se encontró el cVDPV2 en muestras de aguas residuales en Estados Unidos de América, donde se produjo un caso de parálisis flácida aguda por el cVDPV2, Israel y Reino Unido y. La Organización Panamericana de la Salud ha advertido que, tras la caída de las tasas de vacunación (con una cobertura promedio del 80% en el 2022), Brasil, Haití, Perú y República Dominicana corren un riesgo muy alto de reintroducción del poliovirus, en tanto que otros ocho países de América Latina se encuentran en una situación de alto riesgo. La OPV monovalente de tipo 2 de Sabin se ha utilizado para controlar los brotes de VDPV2, pero su empleo también podría ocasionar brotes. Para hacer frente a este problema, se creó una nueva OPV2 (nOPV2) contra el cVDPV2, genéticamente más estable, que en el 2020 se incluyó en la lista de uso en emergencias de la Organización Mundial de la Salud. El despliegue a gran escala de una nueva vacuna incluida en la lista de uso en emergencias con el fin de contener los brotes exige una extraordinaria preparación regulatoria y operativa local.

RESUMO A infecção pelo poliovírus causa paralisia em 1 de cada 200 pessoas infectadas. O uso de vacinas seguras e eficazes, tanto vacinas inativadas contra o poliovírus quanto vacinas orais contendo poliovírus atenuado (VOP), significa que restam apenas dois bolsões de poliovírus selvagem tipo 1, um no Afeganistão e outro no Paquistão. No entanto, a VOP pode reverter à virulência, causando surtos de poliovírus circulante derivado de vacina (cPVDV). No período 2020-2022, o cPVDV tipo 2 (cPVDV2) foi responsável por 97% a 99% dos casos de poliomielite, principalmente na África. Entre janeiro e agosto de 2022, o cPVDV2 foi detectado em amostras de esgoto em Israel, no Reino Unido e nos Estados Unidos da América, onde também houve um caso de paralisia flácida aguda causada pelo cPVDV2. A Organização Pan-Americana da Saúde alertou que, devido à queda nas taxas de vacinação (cobertura média de 80% em 2022), o Brasil, o Haiti, o Peru e a República Dominicana correm um risco muito alto de reintrodução do poliovírus e outros oito países da América Latina correm um risco alto. A VOP monovalente Sabin tipo 2 tem sido usada para controlar surtos de PVDV2, mas seu uso também pode levar a surtos. Para resolver esse problema, foi desenvolvida uma nova VOP2 (nVOP2), mais estável geneticamente, para combater o cPVDV2. Em 2020, a nVOP2 entrou na Lista de Uso Emergencial da Organização Mundial da Saúde. A distribuição de uma nova vacina incluída na Lista de Uso Emergencial em contextos de massa para conter surtos requer medidas originais de preparação operacional e regulatória em âmbito local.

Impact of polio vaccines (oral polio vaccine - OPV or inactivated polio vaccine - IPV) on rotavirus vaccine-associated intussusception.

Although safe, rotavirus vaccines have been associated with increased intussusception risk. In Brazil, after the oral human rotavirus vaccine (OHRV) introduction in the childhood immunization, in 2006, increased intussusception risk was identified after the second OHRV dose, whereas in other countries, higher risk was associated to the first vaccine dose. It was hypothesized that the concomitant use of oral poliovirus vaccine (OPV) in Brazil might explain this difference. In 2012, the inactivated polio vaccine (IPV) was adopted in the first two doses of Brazilian childhood immunization schedule, creating an opportunity to study the subject. Our objective was analyzing the impact of polio vaccines on rotavirus-associated intussusception. We used surveillance data on intussusception in infants living in São Paulo State. Two periods were considered: an OPV-period (March 2006 to June 2012) and an IPV-period (October 2012 to December 2017). The period from June to September 2012 were considered as transition. Self-controlled case series analysis with event-dependent exposure was performed, considering two risk periods (7 and 21 days post-vaccination). We identified 325 intussusception cases in infants reported to the surveillance systems during the study period. The statistical analysis included 221 cases that occurred within 60 days after vaccination. Overall, a higher intussusception risk was observed in the first week after vaccination for both the first (Relative Incidence [RI] = 4.3, 95%CI 2.8-6.5, p < .001) and second vaccine doses (RI = 4.2, 95%CI 2.7-6.4; p < .001). There were no statistically significant differences in intussusception risk according to the rotavirus vaccine dose and the polio vaccine (OPV or IPV) administered concomitantly.

The impact of different IPV-OPV sequential immunization programs on hepatitis A and hepatitis B vaccine efficacy.

In recent years, the Global Polio Eradication Initiative has gradually implemented a global shift in polio immunization programs. Few studies cover polio immunization program impacts on the efficacy of other vaccines. This study investigated whether polio immunization programs affected hepatitis A (HepA) and hepatitis B (HepB) vaccination efficacy. Serum samples were collected from 968 infants before the first dose of polio vaccine, 28 days after completing primary polio immunization, and at 24 months old. Infants were classified into six polio immunization program groups: 1sIPV+2bOPV, 2sIPV+1bOPV, 2sIPV+1tOPV, 1cIPV+2bOPV, 2cIPV+1bOPV, and 2cIPV+1tOPV (sIPV: Sabin inactivated poliovirus vaccine; cIPV: Salk inactivated poliovirus vaccine; b, bivalent; t, trivalent; OPV, oral polio vaccine). No significant differences existed in antibody titers against HepA virus (anti-HAV) among the polio immunization program groups at any of the three time points (pre-first dose [p = 0.412], 28 days after primary immunization [p = 0.676], 24 months old [p = 0.556]). Before the first dose (p = 0.178) and at age 24 months (p = 0.987), no significant differences existed in HepB surface antibody (HBsAb) titers between the six polio immunization program groups). Twenty-eight days after primary immunization, no significant difference existed in HBsAb titers between groups after Bonferroni correction. Following HepA and HepB immunization, anti-HAV and HBsAb positivity reached > 98% in all groups, reflecting effective immunization. Our data suggest that different polio immunization programs did not affect HepA and HepB vaccine efficacy; HepA and HepB vaccines maintained high effectiveness irrespective of polio immunization program. This trial was registered on Clinical Trials.gov: NCT03614702.

Surveillance of adverse events following the introduction of inactivated poliovirus vaccine made from Sabin strains (sIPV) to the Chinese EPI and a comparison with adverse events following inactivated poliovirus vaccine made from wild strains (wIPV) in Jiangsu, China.

One dose of inactivated poliovirus vaccine (IPV) was introduced into the Chinese Expanded Program on Immunization (EPI) in 2016. IPV made from Sabin strains (sIPV) was newly licensed in China and its safety has been concerned. This study aimed to evaluate the safety of sIPV and provide a comparison with conventional IPV made from wild strains (wIPV). We collected all IPV-related AEFI reports in Jiangsu from the Chinese National Adverse Events Following Immunization Information System (CNAEFIS) for 2016-2019. We obtained the administered doses of IPV from the Jiangsu provincial Electronic Immunization Registries System (JSEIRS). The AEFI reporting rates per 100,000 doses of vaccine administered were compared for sIPV and wIPV. A total of 699 sIPV and 908 wIPV AEFI cases were collected by CNAEFIS in Jiangsu during 2016-2019. The overall AEFI reporting rates were 53.02 per 100,000 doses and 41.25 per 100,000 doses for sIPV and wIPV, respectively (P < .001). For both sIPV and wIPV, the AEFIs were mainly classified as common adverse reactions. The reporting rate of common adverse reactions was higher for sIPV than for wIPV (P < .001). The most frequently reported symptoms/signs were fever, persistent crying, injection site erythema/swelling, rash, and injection site induration. Only 1.14% of sIPV-associated and 2.31% of wIPV-associated AEFI cases were diagnosed as serious. No difference in reporting rate was observed for serious AEFIs (P = .272). sIPV has a favorable safety profile, although it exhibits a slightly higher reporting rate of common adverse reactions than wIPV.

Poliomielitis, una historia de inicio triste y final feliz / Poliomyelitis, a story with a sad beginning and a happy ending

Se desarrollan los principales elementos históricos en el estudio y la lucha contra la poliomielitis, su aislamiento por Karl Landsteiner en 1909, la primera vacuna con virus muerto (Jonas Salk, 1955), la segunda vacuna con virus vivo atenuado (Albert Sabin, 1961) y la reducción paulatina de la polio en todo el mundo, hasta llegar a menos de 200 casos al año (virus salvaje)(AU)

The main historical events in the study and fight against polio are shown, its isolation by Karl Landsteiner in 1909, the development of the first vaccine with dead virus (Jonas Salk, 1955), the second vaccine with live attenuated virus (Albert Sabin, 1961) and the gradual reduction of polio worldwide, reaching less than 200 cases a year (wild virus)(AU)

Attitude and perception towards vaccination against poliomyelitis in Peshawar, Pakistan

ABSTRACT OBJECTIVE: This research aimed to quantitatively assess the general public's awareness, attitude and perception of polio and its vaccination in Peshawar KPK, Pakistan. METHODS: We conducted a survey-based study to understand the surge in polio cases from 2015 to 2019 in the Peshawar city of the Khyber Pakhtunkhwa (KPK), Pakistan. A pre-tested questionnaire-based study was conducted in 2019 to assess the attitude and general perception of residents of Peshawar KPK towards polio vaccination. RESULTS: Out of 241 country-wide polio cases, 63 (26.1%) polio cases were reported in Peshawar city from 2015-2019. The questionnaire revealed that individuals between 18-30 years of age had sufficient knowledge (65.1%) about polio. Male and female participants had equal awareness (~ 43%). Participants with higher education (45.9%), those with better financial status (49.5%), individuals with children < 5 years of age (46.4%), and those who had experience of a polio patient (63.1%) had better knowledge. Participants inhabiting the central city were better aware (50.5%) of polio than individuals living in the outskirts. CONCLUSION: The data indicated that poor knowledge and negative attitudes of people towards polio vaccination are the main causes of the polio eradication program's failure. Moreover, religious beliefs, unchecked migration between the Pak-Afghan border, and lack of knowledge about polio vaccination are identified as critical barriers to polio eradication.

Immunogenicity of sequential inactivated and oral poliovirus vaccines (OPV) versus inactivated poliovirus vaccine (IPV) alone in healthy infants: A systematic review and meta-analysis.

BACKGROUND: The emergence of vaccine-associated paralytic poliomyelitis has become an ongoing burden of poliomyelitis. During this special period from OPV to IPV-only immunization schedule, we did a meta-analysis to compare the immunogenicity of sequential IPV and OPV versus IPV alone in healthy infants. METHODS: This systematic review and meta-analysis was registered at international prospective register of systematic reviews (PROSPERO), and the number was CRD42017054889. We performed it as described. RESULTS: Finally, 6 articles were qualified for our review. The results showed that seroconversion rates against all 3 serotype polioviruses were non-inferior and Geometric mean antibody titers (GMTs) were superior in sequential schedules compared with IPV-only schedule. Thus, the sequential vaccination schedules could induce a stronger immunogenicity. CONCLUSIONS: To decrease vaccine-associated and vaccine-derived poliomyelitis, it is a reasonable option to select sequential schedules during this special transition from OPV to IPV-only immunization schedule, which coincides with the current WHO recommendations.

Wild and vaccine-derived poliovirus circulation, and implications for polio eradication.

Polio cases due to wild virus are reported by only three countries in the world. Poliovirus type 2 has been globally eradicated and the last detection of poliovirus type 3 dates to November 2012. Poliovirus type 1 remains the only circulating wild strain; between January and September 2016 it caused 26 cases (nine in Afghanistan, 14 in Pakistan, three in Nigeria). The use of oral polio vaccine (OPV) has been the key to success in the eradication effort. However, paradoxically, moving towards global polio eradication, the burden caused by vaccine-derived polioviruses (VDPVs) becomes increasingly important. In this paper circulation of both wild virus and VDPVs is reviewed and implications for the polio eradication endgame are discussed. Between April and May 2016 OPV2 cessation has been implemented globally, in a coordinated switch from trivalent OPV to bivalent OPV. In order to decrease the risk for cVDPV2 re-emergence inactivated polio vaccine (IPV) has been introduced in the routine vaccine schedule of all countries. The likelihood of re-emergence of cVDPVs should markedly decrease with time after OPV cessation, but silent circulation of polioviruses cannot be ruled out even a long time after cessation. For this reason, immunity levels against polioviruses should be kept as high as possible in the population by the use of IPV, and both clinical and environmental surveillance should be maintained at a high level.

Successes and shortcomings of polio eradication: a transmission modeling analysis.

Polio eradication is on the cusp of success, with only a few regions still maintaining transmission. Improving our understanding of why some regions have been successful and others have not will help with both global eradication of polio and development of more effective vaccination strategies for other pathogens. To examine the past 25 years of eradication efforts, we constructed a transmission model for wild poliovirus that incorporates waning immunity (which affects both infection risk and transmissibility of any resulting infection), age-mediated vaccination rates, and transmission of oral polio vaccine. The model produces results consistent with the 4 country categories defined by the Global Polio Eradication Program: elimination with no subsequent outbreaks; elimination with subsequent transient outbreaks; elimination with subsequent outbreaks and transmission detected for more than 12 months; and endemic polio transmission. Analysis of waning immunity rates and oral polio vaccine transmissibility reveals that higher waning immunity rates make eradication more difficult because of increasing numbers of infectious adults, and that higher oral polio vaccine transmission rates make eradication easier as adults become reimmunized. Given these dynamic properties, attention should be given to intervention strategies that complement childhood vaccination. For example, improvement in sanitation can reduce the reproduction number in problematic regions, and adult vaccination can lower adult transmission.

Ausencia de circulación de poliovirus en departamentos colombianos con coberturas vacunales inferiores a 80% / Absence of poliovirus circulation in Colombian departaments with vaccination coverage below 80%

El presente estudio se propuso explorar la posible circulación silente de poliovirus salvajes y derivados de la vacuna (VDPV, por sus siglas en inglés), en departamentos de Colombia con cobertura de vacunación para polio (OPV, por sus siglas en inglés) menor de 80%. Se colectaron 52 muestras de aguas residuales que se concentraron mediante precipitación con polietilenglicol y cloruro de sodio. La detección viral se realizó mediante aislamiento y la identificación por neutralización del efecto citopático, así como mediante reacción en cadena de la polimerasa convencional y en tiempo real, posterior a la transcripción reversa (TR-RCP y rTR-RCP). Los poliovirus aislados se caracterizaron por secuenciación del gen VP1. En dos de las 52 muestras hubo presencia de poliovirus Sabin 2 con más de 99% de similitud de secuencia con la cepa OPV Sabin 2. Se detectó circulación de enterovirus no polio en 17,3% de las muestras. Los serotipos identificados correspondieron a coxsackievirus B1, echovirus 30 y echovirus 11. No se detectaron evidencias de circulación de VDPV ni poliovirus salvaje en los departamentos de Colombia con coberturas de OPV inferiores a 80%.

This study aims to explore a possible silent circulation of wild and vaccine-derived polioviruses in departments of Colombia with polio vaccination coverage of below 80%. The study collected 52 samples of wastewater concentrated as a result of precipitation with polyethylene glycol and sodium chloride. The viral detection was carried out through isolation and the identification through neutralization of the cytopathic effect, as well as through a conventional polymerase chain reaction following reverse transcription. The isolated polioviruses were characterized by the VP1 gene sequence. In two of the 52 samples, there was a presence of the Sabin type 2 poliovirus with more than 99% sequence similarity with the Sabin type 2 strain polio. Circulation of the nonpolio enterovirus was detected in 17.3% of the samples. The serotypes identified corresponded to coxsackievirus B1, echovirus 30, and echovirus 11. No evidence of the spread of either vaccine-derived poliovirus or wild poliovirus was detected in the departments of Colombia with polio coverage lower than 80%

Pakistan's fight against poliomyelitis: introducing innovative strategies to address challenges and attain the goal of eradication

Pakistan, with Nigeria, India and Afghanistan, is one of the four remaining polio endemic countries in the world. Since the start of polio eradication initiative in 1994, the country has succeeded in reducing the number of polio cases from an estimated 20,000 annually to 89 in 2009. Furthermore, persistent transmission is largely localized to three transmission zones in which ten of the fifteen highest risk areas are situated. Insecurity, operational issues, governance lapses, low routine immunization coverage, inadequate trickle-down of the political commitment existing at the national level to subnational level and extensive population movement are the main barriers to the process. A robust strategicplan was developed for 2010-2012 encompassing district-specific plans and focused strategy on securitycompromised areas, performance-based payment, independent monitoring, attention to migratory populations, social mobilization, and strategic cooperation with Afghanistan. This will provide Pakistan a strong and imminent opportunity to interrupt polio virus circulation

El Dr. Guillermo Contreras Da Silva, una figura señera en la microbiología y la salud pública chilena / Dr Guillermo Contreras Da Silva, a relevant figure in the development of Chilean microbiology

The influence of the work of Dr. Guillermo Contreras Da Silva and his colaborators on the evolution of microbiology in Chile is briefly analyzed. Dr. Contreras was trained in modern virology at Yale University with Dr. J. Melnick under the sponsorhip of the Rockefeller Foundation. During this training, he used serological methods to classify Cocksakie viruses. After his return to Chile, he studied the epidemiology of enteroviruses, including poliovirus. His laboratory, the country's first in modern virology, took an active role in Chile's first Sabin polio vaccination in 1961. Dr. Contreras and his group transformed the teaching and the character of microbiology in Chile from a descriptive medically oriented discipline into an autonomous, quantitative and experimental science. They modernized microbiology with the introduction of molecular biology and microbial genetics and fostered collaborations with allied biological sciences. Dr. Contreras was a Guggenheim Fellow, and until his retirement, was the Chief of the Viral Products Division, Bureau of Biologies, Ottawa, Canada.