Actividades de vigilancia epidemiológica durante la pandemia de gripe (H1N1) 2009 en España. Reflexiones un años después / Epidemiological surveillance activities during the 2009 influenza pandemic in Spain. Lessons learnt one year after

En este artículo se revisan las actuaciones llevadas a cabo en España en materia de vigilancia epidemiológica durante la pandemia de gripe y las recomendaciones de ellas derivadas en los diferentes momentos de la evolución de la misma. El funcionamiento del Sub-comité de Vigilancia, contemplado en el Plan Nacional de Prepara-ción y Respuesta ante una pandemia de gripe, fue clave para la coor-dinación de estas actividades de vigilancia. Este Subcomité se activó de forma inmediata tras la declaración de la alerta y su papel también se describe en este trabajo. La existencia del Plan permitió una respuesta rápida y coordina-da tras la declaración de la alerta. La vigilancia epidemiológica y virológica de la gripe hubo de ir adaptándose a una situación cam-biante, y se pusieron en marcha sistemas adicionales a los de la vigi-lancia habitual de la gripe, tales como la vigilancia individualizada de casos en la comunidad y de casos graves y mortales. Entre las lecciones aprendidas destacan la necesidad de fortale-cer el análisis de los datos que se recogen durante una alerta, la nece-sidad de favorecer el intercambio de información entre los profesio-nales de salud pública y los asistenciales, y de reforzar la capacidad de respuesta para poder disponer de estructuras de salud pública fuertes y consolidadas ante futuras alertas sanitarias(AU)

In this article the actions taken in the area of epidemiological sur-veillance in Spain during the influenza pandemic and the recommen-dations drawn from them during the progression of the pandemic are reviewed. The performance of the Surveillance Subcommittee established in the National Influenza Preparedness and Response Plan was cen-tral to the coordination of these activities. The Surveillance Subcom-mittee was immediately activated when the alert was issued. Its role is also described in this review. The existence of a National Plan allowed a rapid and coordinated response after the alert declaration. The epidemiological and virolo-gical surveillance of the influenza pandemic was adapted to an evol-ving situation. In addition to routine influenza monitoring systems, new surveillance systems were put in place such as a case-based sur-veillance for community influenza cases and a case-based survei-llance for severe cases and deaths due to the pandemic. Among the lessons learned from this pandemic, we would high-light the need to strengthen the timely analysis of data collected during an alert, the need to promote the exchange of information among public health and health care professionals, and to strengthen the response capacity in order to have resilient and consolidated public health structures for future health alerts(AU)

Vigilancia individualizada de los casos iniciales de infección por gripe pandémica (H1N1) 2009 en España, abril-junio 2009 / Enhanced surveillance of initial cases of pandemic influenza (H1N1) 2009 infection in Spain, April-June 2009

Fundamentos: En abril de 2009 se inició en España una nueva estrategia de vigilancia con el objetivo de detectar los casos originados por el virus pandémico (H1N1) 2009 y de implementar las medidas de control adecuadas para contener su transmisión. Se describen las características clínicas y epidemiológicas de los casos confirmados en España notificados por la Red Nacional de Vigilancia Epidemiológica desde el 24 Abril al 30 Junio 2009. Métodos: Como parte de la respuesta inicial de vigilancia a la pandemia, a nivel nacional se recogió información clínica y epide-miológica individualizada de todos los casos en investigación de infección por virus pandémico (H1N1) 2009, así como de sus contactos. Resultados: De los 717 casos confirmados el 91% fueron notificados por 5 Comunidades Autónomas. A 15 de junio de 2009 el 49,1% de los casos pertenecían a brotes en centros educativos. No se detectaron brotes nosocomiales. La mediana de período de incubación fue de 3 días. El 88% de los casos tenía menos de 30 años y el 24,9% eran importados. Los síntomas más frecuentes fueron tos (92%) y fiebre (81,8%). La mediana de duración de síntomas fue de 5 días. Trece casos requirieron ingreso hospitalario y uno falleció. Conclusiones: Durante los primeros meses de pandemia los casos de gripe pandémica presentaron un cuadro leve similar al de la gripe estacional que afectó mayoritariamente a niños y adultos jóvenes. A finales de junio 2009 la aparición de brotes en diferentes colectivos reflejaba la penetración del virus pandémico en la comunidad y el inicio de su circulación(AU)

Background: In April 2009, a new surveillance strategy for the detection of cases of pandemic influenza (H1N1) 2009 infection and for the implementation of appropriate control measures to contain its transmission was initiated in Spain. We describe the clinical and epi-demiological characteristics of confirmed cases in Spain notified by the National Epidemiological Surveillance Network from April 24 to June 30, 2009. Methods: As part of the initial surveillance response to the pan-demic, case-based clinical and epidemiological information was co-llected nationwide on cases under investigation for pandemic virus (H1N1) 2009 infection and their contacts. Results: Of 717 confirmed cases, 91% were notified by 5 Auto-nomous Communities. As of June 15, 49.1% of cases belonged to school outbreaks. No nosocomial outbreaks were detected. The me-dian incubation period was 3 days. Eighty-eight percent of cases were under the age of 30 years, and 24.9% were imported. The most frequent symptoms were cough (92%) and fever (81.8%). The me-dian duration of symptoms was 5 days. Thirteen cases required hos-pitalization and one died. Conclusions: During the first months of the pandemic, pande-mic influenza cases experienced a mild illness similar to seasonal influenza, predominantly affecting children and young adults. By the end of June 2009, the detection of outbreaks in different settings indicated the diffusion of the pandemic virus into the community and the start of its circulation(AU)

Casos de infección por gripe pandémica (H1N1) 2009 hospitalizados en cuidados intensivos en España: factores asociados a riesgo de muerte, abril 2009-enero2010 / Critically ill patients with 2009 pandemic influenza A (H1N1) infection in Spain: factors associated with death, April 2009-January 2010

Fundamento: El análisis de los casos graves de gripe pandémica es necesario para identificar grupos de población vulnerables y adecuar las políticas de prevención y control. Se analizan las características clínicas y epidemiológicas así como los factores asociados a riesgo de muerte en los casos de infección por virus pandémico (H1N1) 2009 hospitalizados en unidades de cuidados intensivos (UCI) en España y notificados entre el 24 de abril de 2009 y el 31 de enero de 2010. Método:En el marco de la estrategia nacional de vigilancia de casos hospitalizados por gripe pandémica, se recogió a nivel nacional informa-ción clínica y epidemiológica individualizada de todos los casos hospitali-zados en UCI por infección por virus pandémico (H1N1) 2009. Resultados:De los 1.231 casos ingresados en una UCI fallecieron 271 (letalidad: 22%). La mediana de edad fue 40 años (rango: 0-90). Un total de 838 (76,3%) pacientes presentaban alguna patología subyacente, siendo la respiratoria la más frecuente (34,1%), seguida en adultos de la obesidad mórbida (18,8%). Un 93,1% recibió tratamiento antiviral y un 25,6% (n=231) lo recibió en 48 horas desde el inicio de síntomas. En el análisis multivariante el cáncer (OR 2,71; IC95% 1,44-5,1), las inmunodeficiencias (OR 2,25; IC95% 1,29-3,92) y la obesidad mórbida (OR 1,79; IC95% 1,13-2,85) estaban asociados significativamente a muerte en los adultos. Conclusión:La caracterización de los casos graves de gripe pandé-mica ha sido clave para identificar como factores de riesgo para sufrir complicaciones y muerte por gripe, la existencia de cáncer e inmunodefi-ciencias y, por primera vez, la obesidad mórbida en personas adultas(AU)

Background: It is necessary to analyse the severe cases of pandemic influenza infection in order to identify vulnerable populations and adapt prevention and control policies accordingly. We analysed the clinical and epidemiological characteristics and risk factors associated with death in patients with 2009 pandemic influenza A (H1N1) infection hospitalised in intensive care units (ICUs) in Spain and reported from 24 April 2009 to 31 January 2010. Methods: As part of the national strategy for surveillance of hospita-lized cases with pandemic influenza, cased-based clinical and epidemiolo-gical information on all cases admitted to an ICU with 2009 pandemic virus (H1N1) infection was collected nationwide. Results: Of 1,231 cases admitted to ICU, 271 died (case fatality ratio, 22%). The median age was 40 years (range: 0-90). A total of 838 (76.3%) patients had an underlying risk condition, being respiratory disease the most frequently reported (34.1%), followed by morbid obesity (18.8%), in adults. Antiviral treatment was given in 93.1% patients and in 25.6% (n = 231) it was initiated within 48 hours of symptoms onset. In a multivariate analysis, cancer (OR 2.71, 95%CI 1.44 to 5.1), immunodeficiency (OR 2.25, 95%CI 1.29 - 3.92) and morbid obesity (OR 1.79, 95%CI 1.13 to 2.85) were significantly associated with death in adults. Conclusions:The characterization of severe pandemic influenza cases has been crucial in identifying as risk factors of complications and death from influenza the presence of cancer and immunodeficiencies and for the first time, morbid obesity in adults(AU)

[Epidemiological surveillance activities during the 2009 influenza pandemic in Spain: lessons learnt one year after]. / Actividades de vigilancia epidemiológica durante la pandemia de gripe (H1N1) 2009 en España: Reflexiones un año después.

In this article the actions taken in the area of epidemiological surveillance in Spain during the influenza pandemic and the recommendations drawn from them during the progression of the pandemic are reviewed. The performance of the Surveillance Subcommittee established in the National Influenza Preparedness and Response Plan was central to the coordination of these activities. The Surveillance Subcommittee was immediately activated when the alert was issued. Its role is also described in this review. The existence of a National Plan allowed a rapid and coordinated response after the alert declaration. The epidemiological and virological surveillance of the influenza pandemic was adapted to an evolving situation. In addition to routine influenza monitoring systems, new surveillance systems were put in place such as a case-based surveillance for community influenza cases and a case-based surveillance for severe cases and deaths due to the pandemic. Among the lessons learned from this pandemic, we would highlight the need to strengthen the timely analysis of data collected during an alert, the need to promote the exchange of information among public health and health care professionals, and to strengthen the response capacity in order to have resilient and consolidated public health structures for future health alerts.

[Enhanced surveillance of initial cases of pandemic influenza (H1N1) 2009 infection in Spain, April-June 2009]. / Vigilancia individualizada de los casos iniciales de infección por gripe pandémica (H1N1) 2009 en España, Abril-Junio 2009.

BACKGROUND: In April 2009, a new surveillance strategy for the detection of cases of pandemic influenza (H1N1) 2009 infection and for the implementation of appropriate control measures to contain its transmission was initiated in Spain. We describe the clinical and epidemiological characteristics of confirmed cases in Spain notified by the National Epidemiological Surveillance Network from April 24 to June 30, 2009. METHODS: As part of the initial surveillance response to the pandemic, case-based clinical and epidemiological information was collected nationwide on cases under investigation for pandemic virus (H1N1) 2009 infection and their contacts. RESULTS: Of 717 confirmed cases, 91% were notified by 5 Autonomous Communities. As of June 15,49.1% of cases belonged to school outbreaks. No nosocomial outbreaks were detected. The median incubation period was 3 days. Eighty-eight percent of cases were under the age of 30 years, and 24.9% were imported. The most frequent symptoms were cough (92%) and fever (81.8%). The median duration of symptoms was 5 days. Thirteen cases required hospitalization and one died. CONCLUSIONS: During the first months of the pandemic, pandemic influenza cases experienced a mild illness similar to seasonal influenza, predominantly affecting children and young adults. By the end of June 2009, the detection of outbreaks in different settings indicated the diffusion of the pandemic virus into the community and the start of its circulation.

[Critically ill patients with 2009 pandemic influenza A (H1N1) infection in Spain: factors associated with death, April 2009-January 2010]. / Casos de infección por gripe pandémica (H1N1) 2009 hospitalizados en cuidados intensivos en España: factores asociados a riesgo de muerte, Abril 2009-Enero 2010.

BACKGROUND: It is necessary to analyse the severe cases of pandemic influenza infection in order to identify vulnerable populations and adapt prevention and control policies accordingly. We analysed the clinical and epidemiological characteristics and risk factors associated with death in patients with 2009 pandemic influenza A (H1N1) infection hospitalised in intensive care units (ICUs) in Spain and reported from 24 April 2009 to 31 January 2010. METHODS: As part of the national strategy for surveillance of hospitalized cases with pandemic influenza, cased-based clinical and epidemiological information on all cases admitted to an ICU with 2009 pandemic virus (H1N1) infection was collected nationwide. RESULTS: Of 1,231 cases admitted to ICU, 271 died (case fatality ratio, 22%). The median age was 40 years (range: 0-90). A total of 838 (76.3%) patients had an underlying risk condition, being respiratory disease the most frequently reported (34.1%), followed by morbid obesity (18.8%), in adults. Antiviral treatment was given in 93.1% patients and in 25.6% (n = 231) it was initiated within 48 hours of symptoms onset. In a multivariate analysis, cancer (OR 2.71, 95%CI 1.44 to 5.1), immunodeficiency (OR 2.25, 95%CI 1.29 - 3.92) and morbid obesity (OR 1.79, 95%CI 1.13 to 2.85) were significantly associated with death in adults. CONCLUSIONS: The characterization of severe pandemic influenza cases has been crucial in identifying as risk factors of complications and death from influenza the presence of cancer and immunodeficiencies and for the first time, morbid obesity in adults.

Evolution of anti-influenza vaccination coverage in Spain from 1993 to 2001.

UNLABELLED: The objective of this study is to describe the evolution of anti-influenza vaccination coverage in Spain from 1993 to 2001. We analysed 55,040 questionnaires taken from the Spanish National Health Surveys from the years 1993, 1995, 1997 and 2001. The reply to the question "Did you vaccinate yourself against influenza during the last campaign?" is the dependent variable. Independent variables were the year of the survey, age, sex and the coexistence of chronic conditions. After adjusting using logistic regression, we found a significant improvement during the study period among those subjects at risk of suffering complications from influenza (OR 1.21). Nevertheless, this increase was essentially at the cost of subjects aged 65 and over. Subjects with high-risk conditions under 65 did not undergo significant changes. CONCLUSIONS: A significant but insufficient improvement has been achieved and this must lead us to consider the possible need to modify anti-influenza vaccination recommendations.

[Evolution of the degrees of influenza vaccine (flu shot) coverage in Spain throughout the 1993-2001 period. Analysis by Autonomous Communities]. / Evolución de las coberturas vacunales antigripales entre 1993-2001 en España. Análisis por Comunidades Autónomas.

BACKGROUND: Influenza (flu) is a disease involving a high morbidity which takes a high toll on healthcare costs for which there is an effective vaccine available. This study is aimed at evaluating the evolution of the different degrees of influenza vaccine (flu shot) coverage in Spain by Autonomous Communities during the 1993-2001 period. METHODS: A total of 42,123 cases from the National Health Survey (NHS) for the years 1993 (n=21,051) and 2001 (n=21,072) were analysed, all of which corresponded to non-institutionalised Spanish adults over 15 years of age. Both surveys are representative at the Autonomous Community level. RESULTS: For the total sample, a vaccine coverage of 17.94% (CI 95% 17.42-18.46) in 1993 and of 19.30% (18.77-19.83) en 2001 was estimated. In the logic regression model, adjusted by age, sex and related chronic disease, significant improvements were found in the degrees of coverage of individuals over 64 years of age (OR = 1.28 CI 95% 1.10-1.50) for Spain as a whole and for five of the seventeen Autonomous Communities between 1993 and 2001. However, no significant changes were found in the degrees of coverage for the group under age 65 with related chronic disease entailing an indication for being administered the vaccine. CONCLUSIONS: A slight yet insufficient improvement in the degrees of coverage among the high-risk groups studied were found to exist both nation-wide in Spain as a whole as well as in the majority of the Autonomous Communities between 1993 and 2001. Degrees of coverage varied greatly among Autonomous Communities. The individual under age 65 with related chronic diseases heightening the risks of suffering from flu-related complications have not improved their degrees of coverage regarding this vaccine during the period studied. The difficulty involved in improving the degrees of coverage among this type of patients might lead us to consider the alternative and potential benefit of lowering the age limit of the current influenza vaccine (flu shot) indication-related recommendations in Spain.

Evolución de las coberturas vacunales antigripales entre 1993-2001 en España. Análisis por comunidades autónomas / Evolution of the degrees of Influenza vaccine (Flu shot) coverage in Spain throughout the 1993-2001 Period. Analysis by Autonomous Communities

Fundamento: La gripe es una enfermedad con una elevada morbilidad y que ocasiona un alto coste sanitario, para la que además se dispone de una vacuna eficaz. El objetivo de este trabajo es evaluar la evolución de las coberturas vacunales antigripales en España por Comunidades Autónomas entre 1993 y 2001. Métodos: Se han analizado un total de 42.123 registros de la Encuesta Nacional de Salud (ENS) de los años 1993 (n=21.051) y 2001 (n=21.072). Todos ellos corresponden a adultos españoles mayores de 15 años no institucionalizados. Ambas encuestas son representativas a nivel de Comunidad Autónoma. Resultados: Para el total de la muestra se estima una cobertura vacunal en 1993 de 17,94 por ciento (IC 95 por ciento 17,42-18,46) y de 19,30 por ciento (18,77-19,83) en 2001. En el modelo de regresión logística, ajustado por edad, género y enfermedad crónica asociada, se observan mejoras significativas en las coberturas del grupo de mayores de 64 años (OR= 1,28 IC 95 por ciento 1,10-1,50) para el total de España y para cinco de las 17 Comunidades Autónomas entre 1993 y 2001. Sin embargo, no encontramos cambios significativos en las coberturas para el grupo de menores de 65 años con enfermedad crónica asociada que supone una indicación para la vacunación. Conclusiones: Tanto en España como en la mayoría de las Comunidades Autónomas entre 1993 y 2001 se observa una ligera pero insuficiente mejoría en las coberturas de vacunación en los grupos de riesgo estudiados. Las Comunidades Autónomas muestran coberturas dispares entre sí. Los sujetos menores de 65 años con enfermedades crónicas asociadas que incrementan el riesgo de sufrir las complicaciones de la gripe no han mejorado las coberturas de esta vacuna durante el periodo de estudio. La dificultad para mejorar las coberturas en este tipo de pacientes podría hacernos considerar la opción y el beneficio potencial de rebajar la edad limite de las actuales recomendaciones de indicación de vacuna antigripal en España (AU)

[A study of whooping cough epidemic outbreak in Castellon, Spain]. / Estudio de un brote epidémico de tos ferina en Castellón.

BACKGROUND: Based on the report of several cases at one school, a study of an epidemic outbreak was started for the purpose of characterizing this outbreak from the person, place and time standpoint, calculating the effectiveness of the immunization and the concordance of the cases with the positive result of the serological study. METHODS: A "case" is defined as being that individual who has a cough fasting for two weeks. A study is made of the spread of the disease by means of the epidemic curve and the effectiveness of the pertussis vaccine. The concordance of the cases and the positive serology is evaluated by way of the Kappa index. RESULTS: From among the students at several schools and those with whom they were living at the time, a total of 130 individuals were surveyed, 94 of whom fit the "case" definition. The average age of the cases was 10.5 years of age, 42.6% being males and 84% school age children, 71.3% showing signs of recent infection (positive IgM), the average length of time since the last whooping cough immunization being 8.25 years. The effectiveness of the whooping cough booster is 66%. The concordance between the cases and the positive results of the serology reveals a Kappa = 0.45. No B. Pertussis was isolated in the 25 throat swab samples. CONCLUSIONS: Classrooms and the family environment are a factor in spreading this disease. The including of a booster at 18 months improves the effectiveness of the whooping cough immunization. The isolation of B. Pertussis is not very frequent, and the serology may be an alternative when this disease is clinically suspected.

Estudio de un brote epidémico de tos ferina en Castellón / A study of a whooping cough epidemic outbreak in Castellon, Spain

Fundamento: A partir de la declaración de varios casos en un centro escolar se inicia el estudio de brote con el objetivo de caracterizar éste desde el punto de vista de persona, lugar y tiempo; se calcula la efectividad de la vacuna, y se estudia la concordancia entre los casos y el resultado positivo del estudio serológico. Métodos: Se define caso a la persona que presenta tos persistente de dos semanas de duración. Se realiza estudio de la difusión de la enfermedad a través de la curva epidémica, y de la efectividad de la dosis de refuerzo de la vacuna antipertussis. La concordancia entre los casos y la serología positiva se evalúa por el índice Kappa. Resultados: Entre los alumnos de varios centros escolares y sus convivientes se encuesta a 130 personas, de los que 94 entran en la definición de caso. La media de edad de los casos es 10,5 años, un 42,6 per cent son varones, el 84 per cent escolares, el 71,3 per cent muestra signos de infección reciente (IgM positiva), y el tiempo medio desde la última dosis de vacuna antipertussis es de 8,25 años. La efectividad de la dosis de refuerzo de la vacuna es del 66 per cent. La concordancia entre los casos y el resultado positivo de la serología muestra un Kappa igual a 0,45. No se aisló B. Pertussis en las 25 muestras de frotis faríngeo. Conclusiones: Las aulas y el medio familiar son un factor de difusión de la enfermedad. La inclusión de una dosis de refuerzo a los 18 meses mejora la efectividad de la vacuna antipertussis. El aislamiento de la B. Pertussis es poco frecuente, y la serología, puede ser una alternativa ante la sospecha clínica de la enfermedad (AU)

Seroepidemiología frente a Citomegalovirus en la Comunidad de Madrid / Seroepidemiology of cytomegalovirus in the autonomous region of Madrid

Fundamento: La infección por citomegalovirus (CMV) es frecuentemente asintomática. Sin embargo, constituye una importante causa de infección congénita y de patología severa en sujetos inmunodeprimidos, por lo que representa un problema en Salud Pública. El objeto de este trabajo fue conocer la prevalencia de IgG frente a CMV (IgG-CMV) en la población general madrileña. Métodos: Estudio transversal en el que se detectó IgG-CMV en una muestra representativa de la población general de la Comunidad de Madrid entre 2 y 60 años (n=2030). Se realizó un muestro bietápico estratificado por conglomerados (octubre de 1993 y febrero de 1994). Para el análisis estadístico se emplearon los test de c2 y c2 de tendencia lineal y se calcularon los porcentajes de seroprevalencia y los odds ratios con intervalos de confianza del 95 por ciento. Resultados: La seroprevalencia global fue del 62,8 por ciento (IC95 por ciento: 60,6-64,9); 66,7 por ciento (IC95 por ciento: 63,7-69,5) en mujeres y del 58,4 por ciento (IC95 por ciento: 55,2-61,5) en hombres. Se observó una asociación significativa entre el aumento de la edad y el incremento de la seroprevalencia. Fueron factores significativos de riesgo la consulta al dentista, antecedentes de cirugía, acupuntura y tatuajes. Los estudios superiores constituyeron un factor protector. Conclusión: Aunque los factores de riesgo detectados indican una posible transmisión vía sanguínea, la elevada prevalencia apunta a la existencia de otras vías mas comunes. El aumento de la seroprevalencia dependiente de la edad sugiere que se produce un número importante de infecciones en la edad adulta. No se puede excluir, sin embargo, que este aumento responda a un efecto cohorte debido a mejoras socioeconómicas similar al detectado para otros virus (AU)