Combating a resurgence of poliomyelitis through public health surveillance and vaccination

Poliomyelitis, or polio, is a highly infectious disease and can result in permanent flaccid paralysis of the limbs. Singapore was certified polio-free by the World Health Organization (WHO) on 29 October 2000, together with 36 other countries in the Western Pacific Region. The last imported case of polio in Singapore was in 2006. Fortunately, polio is vaccine-preventable-the world saw the global eradication of wild poliovirus types 2 and 3 achieved in 2015 and 2019, respectively. However, in late 2022, a resurgence of paralytic polio cases from vaccine-derived poliovirus (VDPV) was detected in countries like Israel and the US (specifically, New York); VDPV was also detected during routine sewage water surveillance with no paralysis cases in London, UK. Without global eradication, there is a risk of re-infection from importation and spread of wild poliovirus or VDPV, or new emergence and circulation of VDPV. During the COVID-19 pandemic, worldwide routine childhood vaccination coverage fell by 5% to 81% in 2020-2021. Fortunately, Singapore has maintained a constantly high vaccination coverage of 96% among 1-year-old children as recorded in 2021. All countries must ensure high poliovirus vaccination coverage in their population to eradicate poliovirus globally, and appropriate interventions must be taken to rectify this if the coverage falters. In 2020, WHO approved the emergency use listing of a novel oral polio vaccine type 2 for countries experiencing circulating VDPV type 2 outbreaks. Environmental and wastewater surveillance should be implemented to allow early detection of "silent" poliovirus transmission in the population, instead of relying on clinical surveillance of acute flaccid paralysis based on case definition alone.

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.

The COVID-19 pandemic and vaccination abandonment in children: spatial heterogeneity maps / Pandemia por COVID-19 e o abandono da vacinação em crianças: mapas da heterogeneidade espacial / Pandemia de COVID-19 y abandono de la vacunación en niños: mapas de heterogeneidad espacial

Abstract Objective: to identify spatial clusters corresponding to abandonment of routine vaccines in children. Method: an ecological study, according to data from the 853 municipalities of a Brazilian state. The records analyzed were those of the multidose pentavalent, pneumococcal 10-valent, inactivated poliomyelitis and oral human rotavirus vaccines of 781,489 children aged less than one year old. The spatial scan statistics was used to identify spatial clusters and assess the relative risk based on the vaccination abandonment indicator. Results: the spatial scan statistics detected the presence of statistically significant clusters for abandonment regarding the four vaccines in all the years analyzed. However, the highest number of clusters with high relative risk estimates was identified in 2020. The Vale do Aço and West, North and West, and Southwest regions stand out for the pentavalent, poliomyelitis and rotavirus vaccines, respectively. Conclusion: in an attempt to mitigate the devastating impact of the COVID-19 pandemic, the immunization program experienced setbacks. The presence of clusters points to the need to implement integrated strategies that may involve different sectors for an active search for children and prevent outbreaks of vaccine-preventable diseases in the near future.

Resumo Objetivo: identificar aglomerados espaciais de abandono de vacinas de rotina em crianças. Método: estudo ecológico, segundo dados dos 853 municípios de um Estado brasileiro. Foram analisados registros das vacinas multidoses pentavalente, pneumocócica 10-valente, vacina inativada contra a poliomielite e vacina oral de rotavírus humano de 781.489 crianças menores de um ano de idade. A estatística scan espacial foi utilizada para identificar agrupamentos espaciais e medir o risco relativo a partir do indicador de abandono de vacinas. Resultados: a estatística scan espacial detectou a presença de aglomerados estatisticamente significativos para o abandono das quatro vacinas em todos os anos analisados. No entanto, o maior número de aglomerados com elevadas estimativas dos riscos relativos foi identificado no ano de 2020. Destaca-se as macrorregiões do Vale do Aço e Oeste; Norte e Oeste; e Sudeste para as vacinas pentavalente, poliomielite e rotavírus, respectivamente. Conclusão: na tentativa de mitigar o impacto devastador da pandemia de COVID-19, o programa de imunização retrocedeu. A presença de aglomerados aponta a necessidade de implementar estratégias integradas que possam envolver diferentes setores para a busca ativa de crianças e evitar surtos de doenças imunopreveníveis no futuro próximo.

Resumen Objetivo: identificar grupos espaciales que abandonaron la vacunación de rutina de los niños. Método: estudio ecológico, basado en los datos de 853 municipios de un Estado brasileño. Se analizaron los registros de vacunas multidosis pentavalente, antineumocócica 10-valente y antipoliomielítica inactivada y vacuna oral contra el rotavirus humano de 781.489 niños menores de un año de edad. Se utilizó la estadística scan espacial para identificar agrupaciones espaciales y medir el riesgo relativo del indicador abandono de la vacunación. Resultados: la estadística scan espacial detectó la presencia de grupos estadísticamente significativos para el abandono de las cuatro vacunas en todos los años analizados. Sin embargo, el mayor número de grupos con estimaciones altas de riesgos relativos se identificó en 2020. Se destacan las macrorregiones del Vale do Aço y Oeste; Norte y Oeste; y Sudeste para las vacunas pentavalente, antipoliomielítica y contra el rotavirus, respectivamente. Conclusión: mientras se intentaba disminuir el impacto devastador de la pandemia de COVID-19, retrocedió el programa de inmunización. La presencia de grupos indica que es necesario implementar estrategias integradas que puedan involucrar a diferentes sectores para la búsqueda activa de niños y evitar brotes de enfermedades inmunoprevenibles en el futuro próximo.

Análisis económico de las vacunas del primer año de vida con componente pertussis en el contexto de la ini-ciativa mundial de erradicación de la poliomielitis en Argentina / Vaccination in children under 1 year with pertussis component in the context of the global initiative for the eradication of poliomyelitis in Argentina: economic analysis

INTRODUCCIÓN: La Iniciativa Mundial de Erradicación de la Polio promueve la introducción de vacuna de polio inactivada (IPV) en sus programas, con la posterior retirada de Sabin (bOPV). OBJETIVO: Construir un modelo de económico que compare diferentes esquemas de vacunación para la prevención de polio y tosferina en el primer año de vida. Material y MÉTODOS: Análisis de cuatro escenarios de vacunación del esquema primario para Argentina, en base a los precios de las vacunas, costos del programa y reactogenicidad de vacuna celular o acelular para Bordetella pertussis: - Escenario 1 (caso base): dos dosis de IPV, una dosis de bOPV y tres dosis de vacuna pentavalente (DTwP-HB-Hib); - Escenario 2: tres dosis IPV y de pentavalente; - Escenario 3: tres dosis de hexavalente (DTaP-HepB-IPV-Hib); - Escenario 4: dos dosis de hexavalente más una dosis de pentavalente más IPV. RESULTADOS: El costo incremental en base al escenario 1 fue de USD 3.716.671; 19.696.668 y 14.383.341 para los escenarios 2, 3 y 4, respectivamente. Para la reactogenicidad, la diferencia fue de USD -14.178.240 comparado el caso base con el escenario 3. DISCUSIÓN: La inversión de incorporación de full IPV y costos asociados se modifica según tipo de vacuna y reactogenicidad asociada al componente B. pertussis.

BACKGROUND: Global Polio Eradication Initiative promotes the introduction of inactivated polio vaccine (IPV) in its programs, with withdrawal of Sabin (bOPV). There is no an economic analysis of the investment related to the incorporation of IPV vaccines together with a whole cell Bordetella pertussis vaccine or combined with acellular hexavalent. AIM: An economic model that compares different vaccination schemes for the prevention of polio and pertussis in the first year of life was carried out. METHODS: Four vaccination scenarios for the primary scheme based on Argentina demographic and costs data were developed: - Scenario 1 (base case): two doses of IPV, one dose of bOPV and three doses of pentavalent (DTwP-HepB-Hib) vaccine; - Scenario 2: three doses of IPV plus three doses of pentavalent; - Scenario 3: three doses of hexavalent; - Scenario 4: two doses of hexavalent plus one dose of pentavalent plus IPV. RESULTS: The incremental cost based on scenario 1 was USD 3.716.671; 19.696.668 and 14.383.341 for scenarios 2, 3 and 4 respectively. In terms of reactogenicity savings was -14.178.240 compared base case with scenario 3. DISCUSSION: Full IPV introduction investment and costs associated were modified according to the type of vaccine and reactogenicity related with the B. pertussis component.

Prevalence of neutralizing antibodies against poliovirus 1, 2, and 3 in healthcare professionals aged 20-50 years / Prevalência de anticorpos neutralizantes contra poliovírus 1, 2 e 3 em profissionais de saúde de 20 a 50 anos de idade

ABSTRACT Objective: To describe the prevalence of neutralizing antibodies against poliovirus (PV1, PV2, and PV3) in blood samples of healthcare professionals aged 20 to 50 years. Methods: Health professionals who serve children at Darcy Vargas Children's Hospital and the Department of Pediatrics of Irmandade da Santa Casa de São Paulo. The sample size was calculated at 323 participants. The Mantel-Haenszel chi-square was used to verify differences between groups. The neutralization reaction detected human poliovirus antibodies. For susceptible individuals, vaccination with the inactivated+triple acellular polio vaccine was performed, and neutralizing antibodies were re-dosed after one week. Results: 333 professionals were studied - 92.8% were immune to poliovirus 1, 86.5% to poliovirus 2, and 63.3% to poliovirus 3; 37% had titers less than 1:8 for any serotype, 5;1% had titers below 1:8 for all three. Vaccination with inactivated polio vaccine was performed for susceptible participants, and neutralizing antibodies were dosed after one week, showing increased titers for all polioviruses. Conclusions: Despite the detection of a significant percentage of individuals with low poliovirus antibody titer, the challenge with vaccination demonstrated immune response compatible with poliovirus immunity.

RESUMO Objetivo: Descrever a prevalência de anticorpos neutralizantes contra poliovírus (tipos 1, 2 e 3) em amostra de sangue de profissionais de saúde com idade de 20 a 50 anos. Métodos: Profissionais de saúde que atendem crianças do Hospital Infantil Darcy Vargas e do Departamento de Pediatria da Irmandade da Santa Casa de São Paulo. O tamanho da amostra foi de 323 participantes. Os anticorpos contra poliovírus humanos foram detectados pela reação de neutralização. Para os indivíduos suscetíveis, foram administradas vacina para poliomielite inativada+tríplice e nova dosagem de anticorpos neutralizantes após uma semana. Utilizou-se o teste do qui-quadrado de Mantel-Haenszel para verificar as diferenças entre os grupos. Resultados: Foram estudados 333 profissionais - 92,8% eram imunes ao poliovírus 1; 86,5%, ao poliovírus 2; 63,57%, ao poliovírus 3; 37% apresentaram títulos inferiores a 1:8 para qualquer sorotipo; 5,1% tinham títulos abaixo de 1:8 para os três. Após a vacinação dos suscetíveis, houve elevação dos títulos para todos os poliovírus. Conclusões: Apesar da detecção de percentual significativo de indivíduos com baixo título de anticorpos para poliovírus, o desafio da vacinação demonstrou resposta imune robusta compatível.

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.

Estado actual de la poliomielitis en Latinoamérica

Resumen La vacuna oral contra el poliovirus (OPV) ha sido fundamental en controlar la epidemia de poliomielitis, y destaca por su seguridad, eficacia, facilidad de administración oral y bajo costo. Sin embargo, a pesar de estas ventajas, al tratarse de una vacuna con virus vivos atenuados, existe la posibilidad de mutaciones que confieran neurovirulencia. Por ende, es importante la vigilancia de parálisis flácida aguda (PFA), ya sea asociada a las vacunas atenuadas (VAPP) o a los virus derivados de vacunas (VDPV). En esta revisión presentamos datos importantes de Latinoamérica en los últimos años, donde se revisan los datos de VDPV de transmisión comunitaria, de origen ambiguo y asociadas con inmunodeficiencias. Debido a la presencia de VDPV, es importante fortalecer el sistema de vigilancia epidemiológica por PFA, con datos muy inferiores a los recomendados en estos últimos años en las Américas. Adicionalmente, es fundamental mejorar las coberturas vacunales para reducir la cantidad de lactantes en riesgo de adquirir poliomielitis. En consecuencia, presentamos las tasas de cobertura vacunal con la vacuna inactivada contra el poliovirus (IPV) en la región y analizamos los programas de vacunación contra la poliomielitis en concordancia con las recomendaciones de la Sociedad Latinoamericana de Infectología Pediátrica (SLIPE; mínimo 3 dosis de IPV) y del Grupo de Expertos en Asesoramiento Estratégico (SAGE) sobre Inmunización de la OMS (mínimo 2 dosis de IPV). El estudio concluye con recomendaciones de los autores para el cambio de OPV a uso exclusivo de IPV, para aumentar las coberturas vacunales y para reforzar la vigilancia por PFA en la región.

Abstract Oral poliovirus vaccine (OPV) has been instrumental in controlling the polio epidemic, and stands out for its safety, efficacy, ease of oral administration, and low cost. However, despite these advantages, as it is a live attenuated virus vaccine, there is the possibility of mutations that confer neurovirulence. Therefore, surveillance for acute flaccid paralysis (AFP) is important, whether associated with live vaccines (VAPP) or vaccine-derived viruses (VDPV). In this review we present important data from Latin America in recent years, where data on VDPV of community transmission, of ambiguous origin and associated with immunodeficiencies are reviewed. Due to the presence of VDPV, it is important to strengthen the epidemiological surveillance system for AFP, with data much lower than those recommended in recent years in the Americas. Additionally, it is essential to improve vaccination coverage to reduce the number of infants at risk of acquiring poliomyelitis. Consequently, we present the vaccination coverage rates with the inactivated vaccine against poliovirus (IPV) in the region and analyze the vaccination programs against poliomyelitis in accordance with the recommendations of the Latin American Society of Pediatric Infectious Diseases (SLIPE; minimum 3 doses of IPV) and the WHO Strategic Advisory Expert Group (SAGE) on Immunization (minimum 2 doses of IPV). The study concludes with recommendations from the authors for the change from OPV to exclusive use of IPV, to increase vaccination coverage and to strengthen surveillance for AFP in the region.

Áreas com queda da cobertura vacinal para BCG, poliomielite e tríplice viral no Brasil (2006-2016): mapas da heterogeneidade regional / Areas with declining vaccination coverage for BCG, poliomyelitis, and MMR in Brazil (2006-2016): maps of regional heterogeneity / Áreas con una caída de la cobertura de vacunación para BCG, poliomielitis y triple vírica en Brasil (2006-2016): mapas de la heterogeneidad regional

A imunização é reconhecida como uma das intervenções mais bem-sucedidas e custo-efetivas, resultando na erradicação e no controle de diversas doenças em todo o mundo. Todavia, uma preocupante redução na cobertura vacinal tem sido observada no Brasil, trazendo o recrudescimento de algumas doenças até então superadas. Dessa forma, no intuito de realizar um diagnóstico situacional que pondere as diferentes regiões do país e a tendência temporal de cobertura vacinal, o presente estudo teve o objetivo de evidenciar áreas com queda da cobertura vacinal de BCG, poliomielite e tríplice viral no Brasil por meio de um estudo ecológico que coletou informações acerca do número crianças de até um ano de idade imunizadas para essas três vacinas, no período entre 2006 e 2016, por município brasileiro. Os dados foram adquiridos por meio do Departamento de Informática do SUS. Foi realizada uma varredura espacial, analisando as variações espaciais nas tendências temporais de cobertura vacinal. Foi observada uma tendência de redução no número de imunizações no Brasil, com quedas de 0,9%, 1,3% e 2,7% ao ano para BCG, poliomielite e tríplice viral, respectivamente. Ademais, aglomerados significativos com tendências temporais de redução da cobertura vacinal foram verificados em todas as cinco regiões brasileiras. O estudo evidencia uma importante redução na cobertura vacinal nos últimos anos, constatando heterogeneidades consideráveis entre os municípios. Dessa forma, uma atenção singular e planejamento estratégico condizente com as características de cada localidade são necessários para o controle tanto da redução de cobertura vacinal como do reaparecimento de doenças no Brasil.

Immunization is known to be one of the most successful and cost-effective health interventions, resulting in the eradication and control of various diseases in the world. However, Brazil has experienced a worrisome drop in vaccination coverage, associated with the resurgence of various previously controlled or eradicated diseases. This study thus conducted a situational diagnosis weighing Brazil's different regions and time trends in vaccination coverage in order to identify areas with reduction in vaccination coverage for BCG, poliomyelitis, and MMR. This ecological study collected data on the number of children up to one year of age who had been vaccinated with these three vaccines from 2006 to 2016, according to municipality (county). Data were obtained from the Brazilian Health Informatics Department. A spatial scan was performed, analyzing spatial variations in the time trends for vaccination coverage. Downward trends were seen in the number of immunizations in Brazil, with reductions of 0.9%, 1.3%, and 2.7% per year for BCG, poliomyelitis, and MMR, respectively. Significant decreases were also seen in all five major geographic regions with time trends in the reduction of vaccination coverage. The study evidenced an important reduction in vaccination coverage in recent years, with major heterogeneity between municipalities. Thus, focused attention and strategic planning in keeping with each local area's characteristics are necessary to address both the reduction of vaccination coverage and the resurgence of vaccine-preventable diseases in Brazil.

La inmunización está reconocida como una de las intervenciones más exitosas y costo-eficientes, consiguiendo la erradicación y control de diversas enfermedades en todo el mundo. Sin embargo, se ha observado una preocupante reducción en la cobertura de la vacunación en Brasil, conllevando el recrudecimiento de algunas enfermedades hasta entonces superadas. De esta forma, con el fin de realizar un diagnóstico situacional, que pondere las diferentes regiones del país y la tendencia temporal de cobertura vacunación, el presente estudio tuvo como objetivo evidenciar áreas con una caída de la cobertura vacunación respecto a BCG, poliomielitis y triple vírica en Brasil. Se trata de un estudio ecológico, que recabó información acerca del número de niños de hasta un año de edad inmunizados con estas tres vacunas, durante el período entre 2006 y 2016, por municipios brasileños. Los datos se consiguieron a través del Departamento de Informática del SUS. Se realizó un barrido espacial, analizando las variaciones espaciales en las tendencias temporales de cobertura de vacunación. Se observó una tendencia de reducción en el número de inmunizaciones en Brasil, con caídas de 0,9%, 1,3% y 2,7% al año, en el caso de BCG, poliomielitis y triple vírica, respectivamente. Además, se verificaron aglomerados significativos con tendencias temporales de reducción en la cobertura de vacunación dentro de las cinco regiones brasileñas. El estudio evidencia una importante reducción en la cobertura de vacunación durante los últimos años, constatando heterogeneidades considerables entre los municipios. De esta forma, una atención singular y planificación estratégica, acorde con las características de cada localidad, son necesarias para el control, tanto de la reducción de la cobertura de vacunación, como del resurgimiento de enfermedades en Brasil.

A erradicação da poliomielite em quatro tempos / La erradicación de la poliomielitis en cuatro tiempos / Poliomyelitis eradication in four stages

O objetivo deste artigo é rever o "estado da arte" dos avanços, obstáculos e estratégias para atingir a erradicação global da pólio. As ações de controle da poliomielite iniciaram na década de 1960 com o advento das duas vacinas antipoliomielíticas, a vacina oral da pólio (VOP) e a vacina inativada da pólio (VIP). No período de 1985 a 2020, são implementadas estratégias para atingir a meta de erradicação do poliovírus selvagem (WPV). Após o sucesso da interrupção da transmissão autóctone do WPV na região da Américas, foi lançada a meta da erradicação global. Descrevemos o processo de erradicação em quatro tempos: (1) O advento das vacinas VIP e VOP iniciou a era do controle da poliomielite; (2) A utilização massiva e simultânea da VOP teve impacto significativo sobre a transmissão do poliovírus selvagem no final da década de 1970 no Brasil; (3) Políticas públicas (nacionais e internacionais) decidem pela erradicação da transmissão autóctone do poliovírus selvagem nas Américas e definem as estratégias epidemiológicas para interromper a transmissão; e (4) A implantação das estratégias de erradicação interrompeu a transmissão autóctone do WPV em quase todas as regiões do mundo, exceto no Paquistão e Afeganistão, onde, em 2020, cadeias de transmissão do WPV1 desafiam as estratégias de contenção do vírus. Por outro lado, a persistência e a disseminação da circulação do poliovírus derivado da VOP, em países com baixa cobertura vacinal, somadas às dificuldades para substituir a VOP pela VIP constituem, atualmente, os obstáculos para a erradicação a curto prazo. Finalmente, discutimos as estratégias para superar os obstáculos e os desafios na era pós-erradicação.

El objetivo de este artículo es revisar el "estado de la cuestión" de los avances, obstáculos y estrategias para alcanzar la erradicación global de la polio. Las acciones de control de la poliomielitis se iniciaron en la década de 1960, con el advenimiento de las dos vacunas antipoliomielíticas, la vacuna oral de la polio (VOP) y la vacuna inactivada de la polio (VIP). En el período de 1985 a 2020, se implementan estrategias para alcanzar la meta de la erradicación del virus de la polio salvaje (WPV). Tras el éxito de la interrupción de la transmisión autóctona del WPV en la región de las Américas, se lanzó la meta de la erradicación global. Describimos el proceso de erradicación en cuatro tiempos: (1) El advenimiento de las vacunas VIP y VOP inició la era del control de la poliomielitis; (2) La utilización masiva y simultánea de la VOP tuvo un impacto significativo sobre la transmisión del virus de la polio salvaje, al final de la década de 1970, en Brasil; (3) Políticas públicas (nacionales e internacionales) deciden la erradicación de la transmisión autóctona del virus de la polio salvaje en las Américas y definen las estrategias epidemiológicas para interrumpir la transmisión; y (4) La implantación de las estrategias de erradicación interrumpió la transmisión autóctona del WPV en casi todas las regiones del mundo, excepto en Paquistán y Afganistán, donde, en 2020, cadenas de transmisión del WPV1 desafían las estrategias de contención del virus. Por otro lado, la persistencia y la diseminación de la circulación del virus de la polio, derivado de la VOP, en países con baja cobertura de vacunas, sumadas a las dificultades para substituir la VOP por la VIP constituyen, actualmente, los obstáculos para la erradicación a corto plazo. Finalmente, discutimos las estrategias para superar los obstáculos y los desafíos en la era poserradicación.

This article's objective is to review the "state of the art" in the progress, obstacles, and strategies for achieving global polio eradication. Poliomyelitis control measures began in the 1960s with the advent of two vaccines, the oral polio vaccine (OPV) and the inactivated polio vaccine (IPV). From 1985 to 2020, strategies were implemented to reach the goal of eradication of wild poliovirus (WPV). Following the success with the interruption of indigenous WPV transmission in the Americas, the goal of global eradication was launched. We describe the process of eradication in four historical stages: (1) The advent of the inactivated and oral polio vaccines launched the age of poliomyelitis control; (2) The massive and simultaneous use of OPV had a significant impact on WPV transmission in the late 1970s in Brazil; (3) Domestic and international public policies set the goal of eradication of indigenous WPV transmission in the Americas and defined the epidemiological strategies to interrupt transmission; and (4) The implementation of eradication strategies interrupted indigenous WPV transmission in nearly all regions of the world except Pakistan and Afghanistan, where in 2020 the WPV1 transmission chains have challenged the strategies for containment of the virus. Meanwhile, the persistence and dissemination of circulation of OPV-derived poliovirus in countries with low vaccination coverage, plus the difficulties in replacing OPV with IPV, are currently the obstacles to eradication in the short term. Finally, we discuss the strategies for overcoming the obstacles and challenges in the post-eradication era.

Padronização de teste para quantificar anticorpos anti-poliovírus utilizando vírus vacinal / Standardization of a test for quantifying the antibodies against poliovirus using the vaccine virus

A poliomielite é uma doença endêmica no Afeganistão e no Paquistão, apesar dos esforços para ser erradicada, representando uma ameaça para outros países principalmente devido às viagens internacionais. A Organização Mundial da Saúde (OMS) tem como objetivo erradicar a poliomielite causada pelo poliovírus selvagem no mundo. O requisito essencial para a erradicação da poliomielite é a eliminação da cepa do poliovírus selvagem, que é empregada no teste padrão-ouro. Com o intuito de auxiliar na erradicação do poliovírus selvagem, o objetivo deste estudo foi modificar o teste padrão-ouro usando o poliovírus derivado da vacina oral atenuada. Foram testados 63 soros pelo ensaio de neutralização utilizando-se antígenos vacinais. A concordância do sorotipo 1 (k=0,74) foi considerada substancial, enquanto o sorotipo 2 (k=1,00) e sorotipo 3 (k= 0,95) foram consideradas quase perfeitas. A sensibilidade dos testes de soroneutralização utilizando os sorotipos 1, 2 e 3 foi de 94,83%, 100,00% e 100,00%, respectivamente. Em conclusão, o ensaio com antígenos vacinais pode ser usado como procedimento laboratorial seguro, especialmente em estudos de vigilância em larga escala.

Poliomyelitis is an endemic disease in Afghanistan and Pakistan in despite of the efforts to eradicate it, and it represents a threat to other countries mainly due to the international trips. The World Health Organization (WHO) aims at eradicating the polio disease worldwide. An essential requirement for eradicating the poliomyelitis is the elimination of the wild poliovirus strain, which is employed in the gold standard test. As a support for the eradication of wild poliovirus, the present study aimed at modifying the gold standard test by using poliovirus derived from the oral attenuated vaccine. Sixty-three sera samples were tested by neutralization assay using vaccine antigens. The degree of agreement of the serotype 1 (k=0.74) was considered substantial, while the serotype 2 (k=1.00) and 3 (k= 0.95) showed almost perfect agreement. The sensitivity of serotypes 1, 2 and 3 was 94.83%, 100.00% and 100.00%, respectively. In conclusion, the assay with the vaccine antigens can be used as a safe application, especially for large-scale surveillance studies.

Remarks on the possibility of introducing the fractionated dose of the inactivated poliomyelitis vaccine in the Latin American Child Immunization Schedule

Abstract Given that the last notified case of poliomyelitis due to wild poliovirus type 2 was in 1999, in 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) recommended the withdrawal of the type 2 component of oral polio vaccine (OPV) and the introduction of a bivalent OPV (bOPV) in all countries by 2016. WHO recommended also that the withdrawal should be preceded by the introduction of at least one dose of inactivated poliovirus vaccine (IPV) in routine immunization schedules. The introduction of IPV prior to the change of the bOPV in 2016 to trivalent OPV (tOPV) was based on the concept of ensuring that a substantial proportion of the population would be protected against type 2 polio after the removal of the type 2 OPV. However, the world's two producers of IPV (Bilthoven Biologicals and Sanofi) have faced problems in the production of this vaccine and therefore reported a reduction of the global supply of IPV. In response to the potential shortage of IPV, at a meeting held on March 10 2017, the SAGE and Technical Advisory Group (TAG) of the Pan American Health Organization (PAHO) urged the countries in the Latin American region to replace the routine administration of the full doses of inactivated polio vaccine (IPV-C) in the immunization schedule (administered by intramuscular route), administering a fraction of the full dose in two intradermal shots (IPV-f). The possibility of this strategy was analyzed by opinion leaders convened by the Paraguayan Society of Pediatrics with the support of the Latin American Society of Pediatric Infectious Diseases (SLIPE) and Latin American Association of Pediatrics (ALAPE). This document presents the results of the discussion.

Using the polio programme to deliver primary health care in Nigeria: implementation research

Objective To evaluate a project that integrated essential primary health-care services into the oral polio vaccine programme in hard-toreach, underserved communities in northern Nigeria.Methods In 2013, Nigeria's polio emergency operation centre adopted a new approach to rapidly raise polio immunity and reduce newborn, child and maternal morbidity and mortality. We identified, trained and equipped eighty-four mobile health teams to provide free vaccination and primary-care services in 3176 hard-to-reach settlements. We conducted cross-sectional surveys of women of childbearing age in households with children younger than 5 years, in 317 randomly selected settlements, pre- and post-intervention (March 2014 and November 2015, respectively). Findings From June 2014 to September 2015 mobile health teams delivered 2 979 408 doses of oral polio vaccine and dewormed 1 562 640 children younger than 5 years old; performed 676 678 antenatal consultations and treated 1 682 671 illnesses in women and children, including pneumonia, diarrhoea and malaria. The baseline survey found that 758 (19.6%) of 3872 children younger than5 years had routine immunization cards and 690/3872 (17.8%) were fully immunized for their age. The endline survey found 1757/3575 children (49.1%) with routine immunization cards and 1750 (49.0%) fully immunized. Children vaccinated with 3 or more doses of oral polio vaccine increased from 2133 (55.1%) to 2666 (74.6%). Households' use of mobile health services in the previous 6 months increased from 509/1472 (34.6%) to 2060/2426(84.9%). Conclusion Integrating routine primary-care services into polio eradication activities in Nigeria resulted in increased coverage for supplemental oral polio vaccine doses and essential maternal, newborn and child health intervention

Protocolo del Sistema Nacional de Vigilancia Epidemiológica de enfermedades inmunoprevenibles. No. 06 / Protocol of the National Epidemiological Surveillance System of immunoprevenible diseases. No. 06

Estos protocolos están dirigido a personal médico, paramédico y otros profesionales que realizan acciones gerenciales y operativas de vigilancia epidemiológica en los servicios de salud del país, y están divididos en varios tomos para dar a conocer y actualizar la identificación y medidas de control para diversos padecimientos a fin de continuar con el mejoramiento de las capacidades técnicas de los trabajadores de salud, que permita planificar la prestación de servicios con decisiones partiendo de un enfoque epidemiológico comprobado, para responder a los cambios de tendencias epidemiológicas y con ello contribuir al fortalecimiento de prácticas asertivas de la salud pública de nuestro país. La vigilancia epidemiológica de las enfermedades prevenibles con vacuna, busca reducir la mortalidad y morbilidad por infecciones inmunoprevenibles. La vigilancia epidemiológica, es fundamental para evaluar el impacto de las intervenciones y la toma de decisiones de acuerdo al análisis permanente de la situación de salud.

Consideraciones referente a la posibilidad de introducir la dosis fraccionada de la vacuna antipoliomielitis inactivada en el calendario de Inmunizaciones del Niño Latinoamericano / Remarks on the possibility of the introduction of fractionated dose of the inactivated poliomyelitis vaccine in the Latin American Child Immunization Schedule

As last notified case of poliomyelitis due to wild poliovirus type 2 was 1999, in 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) recommended the withdrawal of the type 2 component of oral polio vaccine (OPV) and the introduction of bivalent OPV (bOPV) in all countries by 2016. WHO recommended also that the withdrawal should be preceded by the introduction of at least one dose of inactivated poliovirus vaccine (IPV) in routine immunization schedules. The introduction of IPV prior to the change of the bOPV in 2016 to trivalent OPV (tOPV) was based on the concept of ensuring that a substantial proportion of the population would be protected against type 2 polio after the removal of the type 2 OPV. However, the world's two producers of IPV (Bilthoven Biologicals and Sanofi) have faced problems in the production of this vaccine and therefore reported reduction in IPV global supply. In response to the possible shortage of IPV, the SAGE and Technical Adviser Group (TAG) of the Pan American Health Organization (PAHO), in the meeting of March 10, 2017, has urged that countries in the Latinamerican region should replace the routine administration of the full doses of polio inactivated vaccine (IPV-C) in the immunization schedule (administered by intramuscular route) by the administration of a fraction of the full dose in two shots by intradermal route (IPV-f). The possibility of this strategy was analyzed by leaders of opinions gathered by the call of the Paraguayan Pediatric Society with the support of the Latin American Society of Pediatric Infectious Diseases (SLIPE) and Latin American Association of Pediatrics (ALAPE). The results of the discussion are presented in this document.

Nota Histórica / Historical Note

Resumen Una de las grandiosas experiencias a nivel mundial ha sido la vacunación contra la poliomielitis así como también lo fue en su momento la vacunación contra la viruela. Posiblemente con la ayuda de mejores condiciones sanitarias de las poblaciones (al ser una enfermedad de transmisión oral-fecal) estamos en las puertas de la erradicación, pero sobre todo gracias a la intervención con las vacunas contra la polio, tanto la inactivada como la oral. No serán tratados los temas técnicos de las vacunas utilizadas, ambas han sido extraordinarias herramientas para llegar a este momento. No puede ser más oportuna la cita de William Shakespeare: "el pasado es el prólogo", colocada en un mármol a la entrada de un edificio público en Washington DC.

Seronegativity to polio viruses among previously immunized adult candidates to solid organ transplantation

ABSTRACT In the current effort to eliminate polio from the world, it is important to recognize and vaccinate susceptible groups, especially immunocompromised patients living in countries where attenuated polio vaccine is still used. In this report, we describe the frequency of protective antibodies in a small sample of adult SOT candidates in whom previous vaccination could be ascertained. Patients included in this report were selected among the participants of an ongoing prospective study carried out at the Reference Center for Special Immunobiologicals of the Evandro Chagas National Institute of Infectious Diseases in Rio de Janeiro, Brazil. Among the first 100 patients enrolled in this study, only seven adult SOT candidates had proven polio vaccination at childhood. Three of these seven patients (43%) had no protective antibody titers to one or more poliovirus subtype before solid organ transplant. Proven childhood vaccination against polio does not reliably provide lifelong protective antibody titers for adult SOT candidates and should not be used as a criterion to analyze the need for vaccination in this population.

What is the importance of vaccine hesitancy in the drop of vaccination coverage in Brazil? / Qual a importância da hesitação vacinal na queda das coberturas vacinais no Brasil?

ABSTRACT The successful Programa Nacional de Imunizações do Brasil (Brazilian National Immunization Program) has been experiencing a major challenge with regard to vaccination coverage for children, which has been dropping. Several aspects are related, but certainly vaccine hesitancy has been strengthening itself as one of the main concerns of Brazilian public administrators and researchers. Vaccine hesitancy is the delay in acceptance or refusal despite having the recommended vaccines available in health services, being a phenomenon that varies over time, over location and over types of vaccines. Hesitant individuals are between the two poles of total acceptance and refusal of vaccination. Vaccine hesitancy is nothing new in European and North-American countries, and even in Brazil, it has been studied even if under another name. The drop of vaccination coverage observed from 2016 on reiterates the relevance of the theme, which must be better understood through scientific research.

RESUMO O exitoso Programa Nacional de Imunizações do Brasil tem vivenciado grande desafio com relação às coberturas vacinais infantis, que têm apresentado queda. Diversos aspectos estão relacionados, mas certamente a hesitação vacinal vem se fortalecendo como uma das principais preocupações dos gestores e pesquisadores brasileiros. Hesitação vacinal é o atraso em aceitar ou a recusa das vacinas recomendadas quando elas estão disponíveis nos serviços de saúde, sendo um fenômeno que varia ao longo do tempo, do local e dos tipos de vacinas. Indivíduos hesitantes situam-se entre os dois polos de aceitação e recusa total da vacinação. A hesitação vacinal não é novidade em países europeus e norte-americanos e, mesmo no Brasil, ela já vem sendo estudada ainda que sob outra denominação. A queda das coberturas vacinais observadas a partir de 2016 reitera a relevância do tema, que deve ser mais bem compreendido por meio de investigações científicas.