RESUMEN
For more than 20 years, the World Health Organization Western Pacific Region (WPR) has been polio-free. However, two current challenges are still polio-related. First, around half of poliomyelitis elderly survivors suffer late poliomyelitis sequelae with a substantial impact on daily activities and quality of life, experiencing varying degrees of residual weakness as they age. The post-polio syndrome as well as accelerated aging may be involved. Second, after the worldwide Sabin oral poliovirus (OPV) vaccination, the recent reappearance of strains of vaccine-derived poliovirus (VDPV) circulating in the environment is worrisome and able to persistent person-to-person transmission. Such VDPV strains exhibit atypical genetic characteristics and reversed neurovirulence that can cause paralysis similarly to wild poliovirus, posing a significant obstacle to the elimination of polio. Immunization is essential for preventing paralysis in those who are exposed to the poliovirus. Stress the necessity of maintaining high vaccination rates because declining immunity increases the likelihood of reemergence. If mankind wants to eradicate polio in the near future, measures to raise immunization rates and living conditions in poorer nations are needed, along with strict observation. New oral polio vaccine candidates offer a promissory tool for this goal.
Asunto(s)
Poliomielitis , Vacuna Antipolio Oral , Poliovirus , Anciano , Humanos , Parálisis/complicaciones , Poliomielitis/epidemiología , Poliomielitis/prevención & control , Poliomielitis/etiología , Poliovirus/genética , Vacuna Antipolio Oral/efectos adversos , Calidad de VidaRESUMEN
BACKGROUND: To meet the demand for effective and affordable inactivated polio vaccines (IPVs), a reduced dose, aluminium hydroxide (Al(OH)3)-adjuvanted IPV vaccine was developed (IPV-Al, Picovax®) and evaluated in clinical trials. The present trial is an extension of two previous trials (a primary and a booster trial). The aim was to evaluate the persistence of seroprotective antibodies (poliovirus type-specific antibody titre ≥ 8) in 4-year-old children who previously received IPV-Al as primary and booster vaccine doses and to determine the potential booster response and safety profile of an additional dose of IPV-Al. METHODS: Children participating in the two previous trials were invited to receive one additional dose of IPV-Al at 4 years of age (2.5 years after the booster dose) and to have their blood samples collected to measure the pre- and post-vaccination antibody titres. Systemic adverse events (AEs) and local reactogenicity were recorded. RESULTS: At study entry, the seroprotection rates were 89.2%, 100% and 91.1% against poliovirus type 1, 2 and 3, respectively. The additional vaccination with IPV-Al boosted the level of poliovirus type 1, 2 and 3 antibodies to above the seroprotection threshold for all but one subject, i.e., 99.4% for type 1 and 100% for types 2 and 3. The additional dose induced a robust booster response of a 26.3-, 13.9- and 30.9-fold increase in titre for poliovirus types 1, 2 and 3, respectively. The vaccine was well tolerated, with only mild and transient AEs reported. CONCLUSIONS: The present trial demonstrated that the primary vaccination with an aluminium-adjuvanted reduced dose IPV induced a persistent immune memory as evidenced by the robust anamnestic response when the subjects were re-exposed to the antigen 2.5 years after the last dose. Thus, the IPV-Al is an efficient and safe addition to increase the availability of inactivated polio vaccines globally. (ClinicalTrials.gov reg no. NCT04448132).
Asunto(s)
Poliomielitis , Poliovirus , Adyuvantes Inmunológicos , Aluminio , Anticuerpos Antivirales , Preescolar , Humanos , Inmunización Secundaria/efectos adversos , Lactante , Poliomielitis/etiología , Poliomielitis/prevención & control , Vacuna Antipolio de Virus InactivadosAsunto(s)
Humanos , Femenino , Preescolar , Parálisis/etiología , Poliomielitis/etiología , Enfermedades Virales del Sistema Nervioso Central/diagnóstico , Enfermedades Virales del Sistema Nervioso Central/tratamiento farmacológico , Hipotonía Muscular , Enfermedades Neuromusculares/diagnóstico , Enfermedades Neuromusculares/terapia , Infecciones del Sistema Respiratorio , Brotes de Enfermedades , MielitisRESUMEN
In 1988, the World Health Assembly resolved to eradicate poliomyelitis worldwide. One of the main tools used in polio eradication efforts has been the live, attenuated oral poliovirus vaccine (OPV). This inexpensive vaccine is administered easily by mouth, makes recent recipients resistant to infection by wild polioviruses (WPVs), and provides long-term protection against paralytic disease through durable humoral immunity. Nonetheless, rare cases of vaccine-associated paralytic poliomyelitis can occur both among immunologically normal OPV recipients and their contacts and among persons who are immunodeficient. In addition, vaccine-derived polioviruses (VDPVs) can emerge to cause polio outbreaks in areas with low OPV coverage and can replicate for years in persons who are immunodeficient. This report updates previous surveillance summaries and describes VDPVs detected worldwide during April 2011-June 2012. In 2011, a new outbreak of circulating VDPVs (cVDPVs) was identified in Yemen; a second VDPV isolate, related to a previously reported VDPV isolate, signaled an outbreak in Mozambique; and VDPV circulation reemerged in Madagascar. An outbreak that began in Somalia in 2008 continued until December 2011. Outbreaks in Nigeria and the Democratic Republic of the Congo (DRC) identified in 2005 and 2008, respectively, continued in 2012. Niger experienced a new cVDPV importation from Nigeria in 2011. Twelve newly identified persons in six middle-income countries were found to excrete immunodeficiency-associated VDPVs (iVDPVs), and VDPVs were found among healthy persons and environmental samples in 13 countries. To prevent VDPV emergence and spread, all countries should maintain high vaccination coverage against all three poliovirus serotypes; OPV use will be discontinued worldwide once all WPV transmission is interrupted.
Asunto(s)
Brotes de Enfermedades , Poliomielitis/epidemiología , Vacuna Antipolio Oral/efectos adversos , Poliovirus/aislamiento & purificación , África/epidemiología , Asia/epidemiología , Niño , Femenino , Humanos , Huésped Inmunocomprometido , Lactante , Masculino , Poliomielitis/etiología , Poliomielitis/prevención & control , Poliovirus/genética , Vacuna Antipolio Oral/administración & dosificación , Serotipificación , América del Sur/epidemiología , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/efectos adversosRESUMEN
OBJECTIVE: Evaluate the cost-effectiveness of introducing the injectable inactivated polio vaccine (IPV) in Colombia versus the current system based on the use of the oral vaccine (OPV). METHODS: A Markov model was designed, based on a hypothetical cohort of newborns that would receive the IPV or the OPV vaccine, with a two-year follow-up and monthly estimates of the number of cases of vaccine-associated paralytic poliomyelitis (VAPP) that would emerge. The cost was analyzed from the perspective of the insurer (costs throughout life) and society (cases of VAPP and disability-adjusted life years [DALYs] prevented). RESULTS: From 1988 to 1998, some 22.5 million doses of OVP were administered in Colombia and nine cases of VAPP were detected, for a rate of 4.0 yen 10-7 dose. According to the model, 2 to 4 cases of VAPP could be anticipated in the following two years. The cost of treating the VAPP cases would total US$302,008, with the cost of vaccination with OPV coming to US$737,037 and with IPV, US$5,527,777. Vaccination with IPV would prevent 64 DALYs, at a cost of US$71,062 per DALY prevented; preventing one case of VAPP by substituting OPV with IPV would cost between US$1.8 and US$2.2 million. CONCLUSIONS: Substituting OPV with IPV is not a cost-effective measure in Colombia, even if the cellular vaccine against whooping cough currently in use were replaced with an acellular vaccine combined with an IPV.
Asunto(s)
Programas de Inmunización/economía , Poliomielitis/prevención & control , Vacuna Antipolio de Virus Inactivados/economía , Vacuna Antipolio Oral/economía , Colombia/epidemiología , Análisis Costo-Beneficio , Humanos , Recién Nacido , Cadenas de Markov , Poliomielitis/economía , Poliomielitis/epidemiología , Poliomielitis/etiología , Vacuna Antipolio de Virus Inactivados/administración & dosificación , Vacuna Antipolio de Virus Inactivados/efectos adversos , Vacuna Antipolio Oral/administración & dosificación , Vacuna Antipolio Oral/efectos adversos , Evaluación de Programas y Proyectos de Salud/economía , Años de Vida Ajustados por Calidad de Vida , Sensibilidad y EspecificidadRESUMEN
Although acute flaccid paralysis is a manifestation observed in several neurologic and muscular disorders, vaccine-associated paralytic poliomyelitis (VAPP) is an exceedingly rare etiology. In the clinical setting of acute flaccid paralysis, MRI is useful in differentiating between VAPP and other conditions. Additionally, MRI can assess the extent of lesions. However, reports on MRI findings in VAPP are scarce in the pediatric radiology literature. We report a Brazilian infant who developed VAPP 40 days after receiving the first dose of oral polio vaccine (OPV). MR images of the cervical and thoracic spinal cord showed lesions involving the anterior horn cell, with increased signal intensity on T2-weighted sequences. We would like to emphasize the importance of considering VAPP as a differential diagnosis in patients with acute flaccid paralysis and an MRI showing involvement of medulla oblongata or spinal cord, particularly in countries where OPV is extensively administered.
Asunto(s)
Imagen por Resonancia Magnética , Poliomielitis/etiología , Poliomielitis/patología , Vacuna Antipolio Oral/efectos adversos , Médula Espinal/patología , Femenino , Humanos , LactanteRESUMEN
OBJETIVOS: Evaluar la relación costo-efectividad de la introducción de la vacuna inyectable contra la poliomielitis (VIP) en Colombia con respecto al sistema actual basado en el empleo de la vacuna oral (VOP). MÉTODOS: Se diseñó un modelo de Markov basado en una cohorte hipotética de recién nacidos que recibiría la VIP o la VOP con un seguimiento de dos años y estimaciones mensuales del número de casos de poliomielitis paralítica asociada con la vacuna (PPAV). El análisis del costo se realizó desde la perspectiva del asegurador (costos a lo largo de la vida) y la sociedad (casos de PPAV evitados y años de vida ajustados por discapacidad [AVAD] evitados). RESULTADOS: Entre 1988 y 1998 se aplicaron en Colombia 22,5 millones de dosis de la VOP y se detectaron nueve casos de PPAV, para una tasa de 4,0 ¥ 10-7 por dosis. Según el modelo, se podrían esperar entre 2 y 4 casos de PPAV en los dos años de seguimiento. El costo de tratar los casos de PPAV sería de US$ 302 008, con costos de vacunación con la VOP de US$ 737 037 y de US$ 5 527 777 con la VIP. La vacunación con la VIP permitiría evitar 64 AVAD con un costo de US$ 71 062 por AVAD evitado; evitar un caso de PPAV mediante la sustitución de la VOP por la VIP costaría entre US$ 1,8 millones y US$ 2,2 millones. CONCLUSIONES: La sustitución de la VOP por la VIP no es una medida efectiva en función del costo en Colombia, incluso si se sustituyera la vacuna celular contra la tos ferina, actualmente en uso, por una vacuna acelular combinada con una VIP.
OBJECTIVE: Evaluate the cost-effectiveness of introducing the injectable inactivated polio vaccine (IPV) in Colombia versus the current system based on the use of the oral vaccine (OPV). METHODS: A Markov model was designed, based on a hypothetical cohort of newborns that would receive the IPV or the OPV vaccine, with a two-year follow-up and monthly estimates of the number of cases of vaccine-associated paralytic poliomyelitis (VAPP) that would emerge. The cost was analyzed from the perspective of the insurer (costs throughout life) and society (cases of VAPP and disability-adjusted life years [DALYs] prevented). RESULTS: From 1988 to 1998, some 22.5 million doses of OVP were administered in Colombia and nine cases of VAPP were detected, for a rate of 4.0 ¥ 10-7 dose. According to the model, 2 to 4 cases of VAPP could be anticipated in the following two years. The cost of treating the VAPP cases would total US$302 008, with the cost of vaccination with OPV coming to US$737 037 and with IPV, US$5 527 777. Vaccination with IPV would prevent 64 DALYs, at a cost of US$71 062 per DALY prevented; preventing one case of VAPP by substituting OPV with IPV would cost between US$1.8 and US$2.2 million. CONCLUSIONS: Substituting OPV with IPV is not a cost-effective measure in Colombia, even if the cellular vaccine against whooping cough currently in use were replaced with an acellular vaccine combined with an IPV.
Asunto(s)
Humanos , Recién Nacido , Programas de Inmunización/economía , Poliomielitis/prevención & control , Vacuna Antipolio de Virus Inactivados/economía , Vacuna Antipolio Oral/economía , Colombia/epidemiología , Análisis Costo-Beneficio , Cadenas de Markov , Poliomielitis/economía , Poliomielitis/epidemiología , Poliomielitis/etiología , Vacuna Antipolio de Virus Inactivados/administración & dosificación , Vacuna Antipolio de Virus Inactivados/efectos adversos , Vacuna Antipolio Oral/administración & dosificación , Vacuna Antipolio Oral/efectos adversos , Evaluación de Programas y Proyectos de Salud/economía , Años de Vida Ajustados por Calidad de Vida , Sensibilidad y EspecificidadRESUMEN
In 1988, the World Health Assembly resolved to eradicate poliomyelitis worldwide. Subsequently, the Global Polio Eradication Initiative of the World Health Organization (WHO) reduced the global incidence of polio associated with wild polioviruses (WPVs) from an estimated 350,000 cases in 125 countries in 1988 to 1,651 reported cases in 2008 and reduced the number of countries that have never interrupted WPV transmission to four (Afghanistan, India, Nigeria, and Pakistan). Under current WHO plans, when the goal of eradicating all WPV transmission is attained, oral poliovirus vaccine (OPV) use worldwide eventually will be discontinued. However, because vaccine-derived polioviruses (VDPVs) can produce polio outbreaks in areas with low rates of Sabin OPV coverage and can replicate for years in immunodeficient persons, enhanced strategies are needed to limit emergence of VDPVs. This report updates previous summaries and describes VDPVs detected worldwide during January 2008-June 2009. During this period, 1) two new outbreaks of circulating VDPVs (cVDPVs) (accounting for 4-20 cases) were identified in the Democratic Republic of Congo and Ethiopia; 2) a previously identified outbreak in Nigeria ultimately resulted in a cumulative total of 292 cases; 3) two newly identified paralyzed immunodeficient persons in Argentina and the United States were found to excrete VDPVs; and 4) isolated VDPVs were found among persons and environmental samples in 11 countries. All countries need to maintain 1) high rates of poliovirus vaccination coverage to prevent VDPV spread and 2) sensitive poliovirus surveillance to detect VDPVs.
Asunto(s)
Salud Global , Poliomielitis/epidemiología , Vacuna Antipolio Oral , Poliovirus/clasificación , Adulto , África/epidemiología , Argentina/epidemiología , Niño , Brotes de Enfermedades , Monitoreo del Ambiente , Monitoreo Epidemiológico , Europa (Continente)/epidemiología , Femenino , Humanos , Huésped Inmunocomprometido , Lactante , Israel/epidemiología , Masculino , Poliomielitis/etiología , Poliomielitis/prevención & control , Poliovirus/genética , Poliovirus/aislamiento & purificación , Vacuna Antipolio Oral/administración & dosificación , Vacuna Antipolio Oral/efectos adversos , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND: Eight outbreaks of paralytic polio attributable to circulating vaccine-derived poliovirus (cVDPV) have highlighted the risks associated with oral poliovirus vaccine (OPV) use in areas of low vaccination coverage and poor hygiene. As the Polio Eradication Initiative enters its final stages, it is important to consider the extent to which these viruses spread under different conditions, so that appropriate strategies can be devised to prevent or respond to future cVDPV outbreaks. METHODS AND FINDINGS: This paper examines epidemiological (temporal, geographic, age, vaccine history, social group, ascertainment), and virological (type, genetic diversity, virulence) parameters in order to infer the numbers of individuals likely to have been infected in each of these cVDPV outbreaks, and in association with single acute flaccid paralysis (AFP) cases attributable to VDPVs. Although only 114 virologically-confirmed paralytic cases were identified in the eight cVDPV outbreaks, it is likely that a minimum of hundreds of thousands, and more likely several million individuals were infected during these events, and that many thousands more have been infected by VDPV lineages within outbreaks which have escaped detection. CONCLUSIONS: Our estimates of the extent of cVDPV circulation suggest widespread transmission in some countries, as might be expected from endemic wild poliovirus transmission in these same settings. These methods for inferring extent of infection will be useful in the context of identifying future surveillance needs, planning for OPV cessation and preparing outbreak response plans.
Asunto(s)
Poliomielitis/epidemiología , Poliomielitis/etiología , Vacunas contra Poliovirus/efectos adversos , Adolescente , Distribución por Edad , Niño , Preescolar , Brotes de Enfermedades/estadística & datos numéricos , República Dominicana/epidemiología , Egipto/epidemiología , Variación Genética/fisiología , Haití/epidemiología , Humanos , Indonesia/epidemiología , Lactante , Poliomielitis/inmunología , Poliomielitis/virología , Poliovirus/genética , Poliovirus/aislamiento & purificación , Vacunas contra Poliovirus/genética , Vacunas contra Poliovirus/inmunología , Vigilancia de la Población , Clase SocialAsunto(s)
Poliomielitis/patología , Vacuna Antipolio Oral/efectos adversos , Sustancia Negra/patología , Células del Asta Anterior/patología , Atrofia , Tronco Encefálico/patología , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Hipotonía Muscular/etiología , Poliomielitis/etiología , Cuadriplejía/etiología , Médula Espinal/patologíaRESUMEN
OBJECTIVE: To describe the occurrence of vaccine-associated paralytic poliomyelitis (VAPP) in Brazil between 1995 and 2001 and to determine the level of risk for this adverse event. METHODS: This retrospective study utilized data from acute flaccid paralysis investigation and notification records from the Ministry of Health in Brazil. Cases were defined as individuals with a diagnosis of acute flaccid paralysis and a positive stool culture or sequelae compatible with poliomyelitis appearing up to 60 days after the beginning of motor impairment. Also included were individuals in any age range who had contact with vaccinated persons between the 4th and 40th day before the onset of the disease and who developed motor impairment between 4 and 85 days after this contact. Risk was calculated as the ratio between the number of cases and the respective number of doses given in a year, according to the National Immunization Program. RESULTS: Ten cases of VAPP were recorded in the period. The mean age of the cases was 4.7 months. Four cases were associated with the first dose, four with the second dose, and two cases were attributed to contact. In two cases type 1 virus was identified; in one case, type 2; and in three cases, type 3. More than one serotype was isolated in four cases. In all 10 cases the serotype was determined. The observed risk for VAPP during the period studied was 1:5.11 million when considering only the first dose and 1:10.67 million for all the doses. CONCLUSION: The main technical and ethical dilemma of the post-poliomyelitis elimination stage is the occurrence of paralytic cases that result from the vaccine policy itself, whose objective is the eradication of polio.
Asunto(s)
Poliomielitis/epidemiología , Poliomielitis/etiología , Vacuna Antipolio Oral/efectos adversos , Brasil/epidemiología , Humanos , Incidencia , Lactante , Estudios Retrospectivos , Factores de RiesgoRESUMEN
OBJETIVO: Descrever a ocorrência de poliomielite associada ao vírus vacinal no Brasil de 1995 a 2001 e determinar o risco observado para esse evento adverso. MÉTODOS: Este estudo retrospectivo utilizou os dados das fichas de investigação de notificações de paralisias flácidas agudas do Ministério da Saúde do Brasil. Foram considerados como casos os indivíduos com diagnóstico de paralisia flácida aguda com isolamento de vírus vacinal nas amostras de fezes ou seqüela compatível com poliomielite até 60 dias após o início da deficiência motora. Também foram incluídos os indivíduos em qualquer faixa etária que mantiveram contato com indivíduos vacinados entre 4 e 40 dias antes do início da doença e que desenvolveram deficiência motora entre 4 e 85 dias após esse contato. O risco foi calculado como a razão entre o número de casos e as respectivas doses aplicadas por ano, conforme o Programa Nacional de Imunização. RESULTADOS: Foram registrados 10 casos de pólio associada ao vírus vacinal no período. A média de idade foi de 4,7 meses. Quatro casos foram associados à primeira dose; quatro à segunda; e dois casos foram atribuídos a contato. Os sorotipos vacinais isolados foram o tipo 1 (dois casos); 2 (um caso); e 3 (três casos). Mais de um sorotipo foi isolado em quatro casos. Houve determinação dos sorotipos nos 10 casos. O risco observado para a poliomielite associada ao vírus vacinal durante o período foi de 1:5,11 milhões de primeiras doses e de 1:10,67 milhões para o total de doses. CONCLUSÃO: A presença de casos paralíticos provocados pela mesma política vacinal que objetiva a erradicação constitui-se no principal dilema técnico e ético da fase pós-eliminação da poliomielite.
Asunto(s)
Humanos , Lactante , Poliomielitis/epidemiología , Poliomielitis/etiología , Vacuna Antipolio Oral/efectos adversos , Brasil/epidemiología , Incidencia , Estudios Retrospectivos , Factores de RiesgoRESUMEN
To assess areas at risk for poliovirus circulation in Ecuador, we first selected provinces at highest risk based on low immunization coverage with three doses of oral poliovirus vaccine, and a low number of reported cases of acute flaccid paralysis (AFP). Subsequently, we reviewed discharge data for the period 1996--2000 for diagnoses compatible with AFP in the only two national referral hospitals in Quito, and at least two main hospitals in each of the six selected provinces. Environmental samples from one or two cities/towns in each selected province were tested for poliovirus. Of the 14 identified AFP-compatible cases, 8 (57%) had been previously reported and investigated. We visited four out of the six unreported cases; none of those four had sequelae compatible with poliomyelitis. From the 14 environmental samples taken, we identified Sabin viruses in six of the samples; no vaccine-derived polioviruses were isolated. Using this methodology, we found no evidence of undetected poliovirus circulation in Ecuador.
Asunto(s)
Brotes de Enfermedades/prevención & control , Alta del Paciente/estadística & datos numéricos , Poliomielitis/epidemiología , Poliomielitis/prevención & control , Poliovirus/aislamiento & purificación , Vigilancia de la Población/métodos , Reservorios de Enfermedades , Ecuador/epidemiología , Monitoreo del Ambiente/métodos , Monitoreo Epidemiológico , Humanos , Poliomielitis/etiología , Poliomielitis/transmisión , Poliomielitis/virología , Vacuna Antipolio Oral , Medición de Riesgo/métodos , Factores de Riesgo , Vacunación/estadística & datos numéricosRESUMEN
Within the past 4 years, poliomyelitis outbreaks associated with circulating vaccine-derived polioviruses (cVDPVs) have occurred in Hispaniola (2000-01), the Philippines (2001), and Madagascar (2001-02). Retrospective studies have also detected the circulation of endemic cVDPV in Egypt (1988-93) and the likely localized spread of oral poliovirus vaccine (OPV)-derived virus in Belarus (1965-66). Gaps in OPV coverage and the previous eradication of the corresponding serotype of indigenous wild poliovirus were the critical risk factors for all cVDPV outbreaks. The cVDPV outbreaks were stopped by mass immunization campaigns using OPV. To increase sensitivity for detecting vaccine-derived polioviruses (VDPVs), in 2001 the Global Polio Laboratory Network implemented additional testing requirements for all poliovirus isolates under investigation. This approach quickly led to the recognition of the Philippines and Madagascar cVDPV outbreaks, but of no other current outbreaks. The potential risk of cVDPV emergence has increased dramatically in recent years as wild poliovirus circulation has ceased in most of the world. The risk appears highest for the type 2 OPV strain because of its greater tendency to spread to contacts. The emergence of cVDPVs underscores the critical importance of eliminating the last pockets of wild poliovirus circulation, maintaining universally high levels of polio vaccine coverage, stopping OPV use as soon as it is safely possible to do so, and continuing sensitive poliovirus surveillance into the foreseeable future. Particular attention must be given to areas where the risks for wild poliovirus circulation have been highest, and where the highest rates of polio vaccine coverage must be maintained to suppress cVDPV emergence.
Asunto(s)
Brotes de Enfermedades , Poliomielitis/epidemiología , Vacuna Antipolio Oral/efectos adversos , Poliovirus/aislamiento & purificación , Niño , República Dominicana/epidemiología , Egipto/epidemiología , Haití/epidemiología , Humanos , Programas de Inmunización , Madagascar/epidemiología , Filipinas/epidemiología , Polonia/epidemiología , Poliomielitis/etiología , Poliomielitis/prevención & control , Poliomielitis/transmisión , Poliovirus/genética , Poliovirus/patogenicidad , ARN Viral/análisis , Factores de Riesgo , Esparcimiento de Virus , Organización Mundial de la SaludRESUMEN
We describe a case of poliomyelitis in a 3-year-old Argentinean boy with X-linked hypogammaglobulinemia. The child had no history of polio vaccination, but a poliovirus isolated from a stool sample had 97.2% genetic similarity to the Sabin 1 vaccine strain. According to the WHO definition, this is the first case reported of a vaccine-derived poliovirus infection recorded in continental Latin America.