Marked increase in cryptosporidiosis cases, Spain, 2023.

BackgroundBy mid-September 2023, several event notifications related to cryptosporidiosis had been identified from different regions in Spain. Therefore, a request for urgent notification of cryptosporidiosis cases to the National Surveillance Network was launched.AimWe aimed at assessing the extent of the increase in cases, the epidemiological characteristics and the transmission modes and compared to previous years.MethodsWe analysed data on case notifications, outbreak reports and genotypes focusing on June-October 2023 and compared the results to 2016-2022.ResultsIn 2023, 4,061 cryptosporidiosis cases were notified in Spain, which is an increase compared to 2016-2022. The cumulative incidence was 8.3 cases per 100,000 inhabitants in 2023, sixfold higher than the median of 1.4 cases per 100,000 inhabitants 2016-2022. Almost 80% of the cases were notified between June and October. The largest outbreaks were related to contaminated drinking water or swimming pools. Cryptosporidium hominis was the most common species in the characterised samples (115/122), and the C. hominis IfA12G1R5 subtype, previously unusual in Spain, was detected from 76 (62.3%) of the 122 characterised samples.ConclusionsA substantial increase in cryptosporidiosis cases was observed in 2023. Strengthening surveillance of Cryptosporidium is essential for prevention of cases, to better understand trends and subtypes circulating and the impact of adverse meteorological events.

Influenza A(H5N1) detection in two asymptomatic poultry farm workers in Spain, September to October 2022: suspected environmental contamination.

In autumn 2022, the Spanish Influenza National Reference Laboratory (NRL) confirmed the detection of influenza A(H5N1) in samples from two asymptomatic workers linked to an outbreak in a poultry farm in Spain. Nasopharyngeal swabs were taken according to a national screening protocol for exposed workers. Absence of symptoms, low viral load and negative serology in both workers suggested environmental contamination. These findings motivated an update of the early detection strategy specifying timing and sampling conditions in asymptomatic exposed persons.

Lifting COVID-19 mitigation measures in Spain (May-June 2020).

Introduction: The state of alarm was declared in Spain due to the COVID-19 epidemic on March 14, 2020, and established population confinement measures. The objective is to describe the process of lifting these mitigation measures. Methods: The Plan for the Transition to a New Normality, approved on April 28, contained four sequential phases with progressive increase in socio-economic activities and population mobility. In parallel, a new strategy for early diagnosis, surveillance and control was implemented. A bilateral decision mechanism was established between the Spanish Government and the autonomous communities (AC), guided by a set of qualitative and quantitative indicators capturing the epidemiological situation and core capacities. The territorial units were established ad-hoc and could be from Basic Health Zones to entire AC. Results: The process run from May 4 to June 21, 2020. AC implemented plans for reinforcement of core capacities. Incidence decreased from a median (50% of territories) of 7.4 per 100,000 in 7 days at the beginning to 2.5 at the end. Median PCR testing increased from 53% to 89% of suspected cases and PCR total capacity from 4.5 to 9.8 per 1000 inhabitants weekly; positivity rate decreased from 3.5% to 1.8%. Median proportion of cases with traced contacts increased from 82% to 100%. Conclusion: Systematic data collection, analysis, and interterritorial dialogue allowed adequate process control. The epidemiological situation improved but, mostly, the process entailed a great reinforcement of core response capacities nation-wide, under common criteria. Maintaining and further reinforcing capacities remained crucial for responding to future waves.

Introducción: El 14 de marzo de 2020 España declaró el estado de alarma por la pandemia por COVID-19 incluyendo medidas de confinamiento. El objetivo es describir el proceso de desescalada de estas medidas. Métodos: Un plan de transición hacia una nueva normalidad, del 28 de abril, incluía 4 fases secuenciales incrementando progresivamente las actividades socioeconómicas y la movilidad. Concomitantemente, se implementó una nueva estrategia de diagnóstico precoz, vigilancia y control. Se estableció un mecanismo de decisión bilateral entre Gobierno central y comunidades autónomas (CCAA), guiado por un panel de indicadores cualitativos y cuantitativos de la situación epidemiológica y las capacidades básicas. Las unidades territoriales evaluadas comprendían desde zonas básicas de salud hasta CCAA. Resultados: El proceso se extendió del 4 de mayo al 21 de junio y se asoció a planes de refuerzo de las capacidades en las CCAA. La incidencia disminuyó de una mediana inicial de 7,4 por 100.000 en 7 días a 2,5 al final del proceso. La mediana de pruebas PCR aumentó del 53% al 89% de los casos sospechosos, y la capacidad total de 4,5 a 9,8 pruebas semanales por 1.000 habitantes; la positividad disminuyó del 3,5% al 1,8%. La mediana de casos con contactos trazados aumentó del 82% al 100%. Conclusión: La recogida y análisis sistemático de información y el diálogo interterritorial logaron un adecuado control del proceso. La situación epidemiológica mejoró, pero sobre todo, se aumentaron las capacidades, en todo el país y con criterios comunes, cuyo mantenimiento y refuerzo fue clave en olas sucesivas.

Epidemiologic Features and Control Measures during Monkeypox Outbreak, Spain, June 2022.

During June 2022, Spain was one of the countries most affected worldwide by a multicountry monkeypox outbreak with chains of transmission without identified links to disease-endemic countries. We provide epidemiologic features of cases reported in Spain and the coordinated measures taken to respond to this outbreak.

Mpox (formerly monkeypox) in women: epidemiological features and clinical characteristics of mpox cases in Spain, April to November 2022.

Over 79,000 confirmed cases of mpox were notified worldwide between May and November 2022, most of them in men who have sex with men. Cases in women, for whom mpox might pose different risks, are rare, and Spain has reported more than one third of those in Europe. Using surveillance data, our study found similar time trends, but differences in delay of diagnosis, sexual transmission and signs and symptoms between men and women.

Unprecedented increase of West Nile virus neuroinvasive disease, Spain, summer 2020.

Cases of West Nile neuroinvasive disease (WNND) in Spain increased in summer 2020. Here we report on this increase and the local, regional and national public health measures taken in response. We analysed data from regional surveillance networks and the National Epidemiological Surveillance Network, both for human and animal West Nile virus (WNV) infection. During the 2020 season, a total of 77 human cases of WNV infection (median age 65 years; 60% males) were detected in the south-west of Spain; 72 (94%) of these cases developed WNND, presenting as meningoencephalitis, seven of which were fatal. In the previous two decades, only six human cases of WNND were detected in Spain. Reduced activities for vector control this season, together with other factors, might have contributed to the massive increase. Public health measures including vector control, campaigns to raise awareness among physicians and the general population, and interventions to ensure the safety of donations of blood products, organs, cells and tissues were effective to reduce transmission. Going forward, maintenance of vector control activities and an update of the vector-borne diseases response plan in Spain is needed.

An imported case of vaccine-derived poliovirus type 2, Spain in the context of the ongoing polio Public Health Emergency of International Concern, September 2021.

The monthly retrospective search for unreported acute flaccid paralysis (AFP) cases conducted as a complementary component of the Spanish AFP surveillance system identified a case of AFP in a child admitted in Spain from Senegal during August 2021. Vaccine-derived poliovirus 2 was identified in the stool in September 2021. We present public health implications and response undertaken within the framework of the National Action Plan for Polio Eradication and the Public Health Emergency of International Concern.

First cases of coronavirus disease 2019 (COVID-19) in the WHO European Region, 24 January to 21 February 2020.

In the WHO European Region, COVID-19 surveillance was implemented 27 January 2020. We detail the first European cases. As at 21 February, nine European countries reported 47 cases. Among 38 cases studied, 21 were linked to two clusters in Germany and France, 14 were infected in China. Median case age was 42 years; 25 were male. Late detection of the clusters' index cases delayed isolation of further local cases. As at 5 March, there were 4,250 cases.

Dispersion of Aedes albopictus in the Spanish Mediterranean Area.

Emergence and re-emergence of arboviral disease in new areas of southern Europe is becoming a public health problem. Since Aedes albopictus was first detected in 2004 in Catalonia, it has spread along the Spanish Mediterranean coast. Results of an entomological surveillance carried out by the Spanish Ministry of Health to monitor the expansion of Ae. albopictus along the Spanish Mediterranean coast between 2009 and 2012 are presented. Besides the new locations in Valencia and Murcia regional communities, it was identified in five municipalities in the Balearic Islands in 2012. A comprehensive plan aiming the control of invasive vector-borne diseases including entomological surveillance should be considered.

Updated distribution of Aedes albopictus (Diptera: Culicidae) in Spain: new findings in the mainland Spanish Levante, 2013.

In 2004, Aedes (Stegomyia) albopictus (Skuse, 1894) was observed for the first time in Catalonia, northeastern Spain. A decade later, it has spread throughout the eastern Mediterranean region of the country and the Balearic Islands. Framed within a national surveillance project, we present the results of monitoring in 2013 in the autonomous communities of the mainland Levante. The current study reveals a remarkable increase in the spread of the invasive mosquito in relation to results from 2012; the species was present and well-established in 48 municipalities, most of which were along the Mediterranean coastline from the Valencian Community to the Region of Murcia.

Comparative severity of COVID-19 cases caused by Alpha, Delta or Omicron SARS-CoV-2 variants and its association with vaccination.

BACKGROUND: This study compares the severity of SARS-CoV-2 infections caused by Alpha, Delta or Omicron variants in periods of co-circulation in Spain, and estimates the variant-specific association of vaccination with severe disease. METHODS: SARS-CoV-2 infections notified to the national epidemiological surveillance network with information on genetic variant and vaccination status were considered cases if they required hospitalisation or controls otherwise. Alpha and Delta were compared during June-July 2021; and Delta and Omicron during December 2021-January 2022. Adjusted odds ratios (aOR) were estimated using logistic regression, comparing variant and vaccination status between cases and controls. RESULTS: We included 5,345 Alpha and 11,974 Delta infections in June-July and 5,272 Delta and 10,578 Omicron in December-January. Unvaccinated cases of Alpha (aOR: 0.57; 95% CI: 0.46-0.69) or Omicron (0.28; 0.21-0.36) had lower probability of hospitalisation vs. Delta. Complete vaccination reduced hospitalisation, similarly for Alpha (0.16; 0.13-0.21) and Delta (June-July: 0.16; 0.14-0.19; December-January: 0.36; 0.30-0.44) but lower from Omicron (0.63; 0.53-0.75) and individuals aged 65+ years. CONCLUSION: Results indicate higher intrinsic severity of the Delta variant, compared with Alpha or Omicron, with smaller differences among vaccinated individuals. Nevertheless, vaccination was associated to reduced hospitalisation in all groups.

Lifting COVID-19 mitigation measures in Spain (May-June 2020).

INTRODUCTION: The state of alarm was declared in Spain due to the COVID-19 epidemic on March 14, 2020, and established population confinement measures. The objective is to describe the process of lifting these mitigation measures. METHODS: The Plan for the Transition to a New Normality, approved on April 28, contained four sequential phases with progressive increase in socio-economic activities and population mobility. In parallel, a new strategy for early diagnosis, surveillance and control was implemented. A bilateral decision mechanism was established between the Spanish Government and the autonomous communities (AC), guided by a set of qualitative and quantitative indicators capturing the epidemiological situation and core capacities. The territorial units were established ad-hoc and could be from Basic Health Zones to entire AC. RESULTS: The process run from May 4 to June 21, 2020. AC implemented plans for reinforcement of core capacities. Incidence decreased from a median (50% of territories) of 7.4 per 100,000 in 7 days at the beginning to 2.5 at the end. Median PCR testing increased from 53% to 89% of suspected cases and PCR total capacity from 4.5 to 9.8 per 1000 inhabitants weekly; positivity rate decreased from 3.5% to 1.8%. Median proportion of cases with traced contacts increased from 82% to 100%. CONCLUSION: Systematic data collection, analysis, and interterritorial dialogue allowed adequate process control. The epidemiological situation improved but, mostly, the process entailed a great reinforcement of core response capacities nation-wide, under common criteria. Maintaining and further reinforcing capacities remained crucial for responding to future waves.

[Lessons learnt from COVID-19 surveillance. Urgent need for a new public health surveillance. SESPAS Report 2022]. / Lecciones de la vigilancia de la COVID-19. Necesidad urgente de una nueva vigilancia en salud pública. Informe SESPAS 2022.

In this article we provide the most important epidemiological aspects in the first phases of the pandemic and some preliminary reflections from the Coordinating Centre for Health Alerts and Emergencies, the unit that has coordinated surveillance at the national level. COVID-19 has brought to light the weaknesses in the surveillance system and how difficult it is to manage a health crisis in the absence of a robust public health structure. The commitment of public health professionals during this epidemic has made up for the lack of resources in many occasions, and has evidenced the need to incorporate new professional profiles to surveillance teams. The need to rapidly adapt has achieved an improvement in existing systems and the development of new tools and new systems. These need to turn into structural changes that improve the quality of surveillance, decreasing territorial gaps and ensuring a better and coordinated response to future health crises. It is urgent to incorporate tools for process automation and to grant timely availability of data. To that end, public health and epidemiological surveillance must participate in the process of digital development within the National Health System. Profound changes are needed in public health surveillance, which has to be integrated in all healthcare levels. It is also important to strengthen the capacity for analysis by promoting alliances and joint actions. During this alert, the importance of coordination in public health in a decentralized country has been evident. At international level, it is necessary to review the tools to share data to coordinate an alert from the early stages.

[The impact of COVID-19 on sick leave of the persons working in nursing homes in Spain. Usefulness of sick leave for the surveillance of the pandemic evolution.] / El impacto de la Covid-19 en la incapacidad temporal de las personas que trabajan en centros socio-sanitarios en España. Utilidad de la incapacidad temporal para el seguimiento de la evolución de la pandemia.

OBJECTIVE: The nursing homes represented high-risk settings for SARS-CoV-2 infection, both for residents and for the employees. The COVID-19 impact on long-term care facilities (LTCFs) is evaluated, measured through the employees sick leave (SL). The pandemic evolution in the general population aged between 16 and 65 years was analyzed together with the sick leave to assess the latter as a complementary indicator of the SARS-CoV-2 surveillance. METHODS: A descriptive study of all sick leave processes due to COVID-19 recorded between February 15th 2020 and May 1st 2021 in nursing homes was carried out. The close contact sick leave/infection sick leave ratios, the 100,000 affiliated/occupied sick leave rates were computed and compared with the COVID-19 cases cumulative incidence notified to the National Network of epidemiological Surveillance (RENAVE). RESULTS: 261.892 SL processes were recorded. The close contact sick leave/infection sick leave median ratio in nursing homes was 1.8 (Interquartile range, ICR: 1.1-3.3), with values lower than 1 at certain periods. The infection sick leaves were higher in number and ratio and prior to the cases recorded in RENAVE. The sick leave ratio ranged between 81.679/100.000 occupied in nursing homes with medical care and 4.895/100.000 in other residential facilities. CONCLUSIONS: The results confirmed the dramatic impact of COVID-19 in nursing homes and the inequalities characterizing this impact. They also confirmed the potential use of sick leave as an alternative source for epidemiological and public health surveillance, especially now, when the transition of the COVID-19 surveillance to a system not including universal individual surveillance is being discussed.

OBJETIVO: Los centros sociosanitarios representaron entornos de alto riesgo de contagio por SARS-CoV-2, tanto para los residentes como para las personas trabajadoras. Se evaluó el impacto en términos de incapacidad temporal (IT) por COVID-19 en las personas que trabajan en centros sociosanitarios y se comparó con la evolución de la pandemia en la población general de 16 a 65 años, para valorar la utilidad de la IT como indicador complementario de la epidemia por SARS-CoV-2. METODOS: Se realizó un estudio descriptivo de todos los procesos de incapacidad temporal por COVID-19 registrados entre el 15 de febrero de 2020 y el 1 de mayo de 2021 en establecimientos residenciales. Se obtuvieron las ratios de incapacidad temporal por contacto estrecho /incapacidad temporal por infección, las tasas de incapacidad temporal por 100.000 afiliados/ocupados y se compararon con la incidencia acumulada de casos COVID-19 notificados a la Red Nacional de Vigilancia Epidemiológica (RENAVE). RESULTADOS: Se registraron 261.892 procesos de incapacidad temporal. La mediana de la ratio de incapacidad temporal por contacto estrecho /incapacidad temporal por infección en residencias fue de 1,8 (Rango intercuartílico, RIC: 1,1-3,3), con valores menores a 1 en periodos. Las IT por infección fueron superiores en número, tasa y anteriores en el tiempo a los casos registrados en RENAVE. Por tipo de residencia, la tasa de incapacidad temporal osciló entre 81.679/100.000 ocupados en asistencia en establecimientos residenciales con cuidados sanitaros y 4.895/100.000 en otros establecimientos residenciales. CONCLUSIONES: Los resultados confirmaron el enorme impacto que tuvo la COVID-19 en los centros sociosanitarios y la desigualdad que ha caracterizado este impacto. Apoyan también la posible utilización de la incapacidad temporal como fuente de información alternativa para la vigilancia epidemiológica y de salud pública, lo cual resulta de especial interés en este momento en el que se está planteando una transición en la vigilancia del COVID-19 hacia un sistema que ya no incluya una vigilancia individualizada universal.

[Long-term care facilities (LTCF) for the elderly: the surveillance of communicable diseases as part of health care and protection.] / Centros residenciales de mayores: la vigilancia de las enfermedades transmisibles como parte del cuidado y la protección de la salud.

During the last decades, healthcare has undergone important changes. Increased life expectancy has given rise to an aging population that, according to the United Nations, is about to become one of the most important social transformations of the 21st century. Globally, there were 727 million people aged 65 or over in 2020 (9.3% of the total population) and this is estimated to increase to 16% by 2050 . In the European Union (EU), the percentage of the population aged 65 or over has increased from 9.6% in 1960 to 20.3% in 2019 and is projected to increase to 31.3% by 2100. We are also witnessing a process of aging of the elderly population, with a proportion of very old people (those aged 80 and over) in the total population of the European Union of 5.8% in 2019 . Spain is one of the countries with the highest proportion of older people, with a percentage of citizens aged 65 or over in 2020 of 19.6% of the total population, and with a projection of 26.5% for 2035. Almost a third of this population (6%) are 80 years or older.

Durante las últimas décadas la asistencia sanitaria ha sufrido importantes cambios. La mayor esperanza de vida ha dado lugar a un envejecimiento de la población que, según las Naciones Unidas, está a punto de convertirse en una de las más importantes transformaciones sociales del siglo XXI. A nivel mundial, había 727 millones de personas de 65 años o más en 2020 (un 9,3% de la población total) y se estima que aumente al 16% en 2050 . En la Unión Europea (UE), el porcentaje de población de 65 años o más se ha incrementado de un 9,6% en 1960 a un 20,3% en 2019 y se proyecta que aumente a un 31,3% para 2100. Asistimos además a un proceso de envejecimiento de la población mayor, con una proporción de personas muy mayores (aquellas de 80 años y más) en la población total de la Unión Europea del 5,8% en 2019 . España es uno de los países con una mayor proporción de personas mayores, con un porcentaje de ciudadanos de 65 años o más en 2020 del 19,6% del total de la población, y con una proyección del 26,5% para 2035. Casi un tercio de esta población (6%) tienen 80 años o más.

[COVID-19 outbreaks in occupational settings in Spain, one year of follow-up (June 2020-June 2021).] / Brotes de COVID-19 en el ámbito laboral en España, un año de seguimiento (junio 2020-junio 2021).

COVID-19 outbreak surveillance in Spain was established with the main objective of characterizing outbreaks and the settings in which they occurred, in order to identify those population groups at highest risk to support them with the implementation of preventive and control measures. Between June 2020 and June 2021, 55,824 outbreaks were reported, with 414,882 cases in all settings. About 12.5% were reported in an occupational setting and within this, most of them were identified in the industry and building sectors. The outbreaks that had a greater impact were those that took place both in agriculture and in the meat industry, where there is a higher risk of exposure due to living and working conditions. Outbreaks in the catering and home care sectors were also frequent. Since the beginning, there was coordination between all stakeholders involved in the management of the pandemic, in order to implement prevention and control measures, as well as social protection measures. In addition, special actions were implemented in the most vulnerable sectors. Despite the work carried out, the presence of outbreaks in these sectors continues, although they are smaller than the previous pandemic phase. Due to this, there is needed to continue strengthening the inter-sectoral coordination structures and mechanisms to ensure the implementation of those measures that contribute to the containment of the pandemic.

La vigilancia de brotes COVID-19 en España se estableció con el objetivo de caracterizar los brotes y los ámbitos en los que ocurrían, con el propósito de identificar aquellos grupos de población con mayor riesgo para apoyar la toma de medidas de prevención y control. Entre junio de 2020 y junio de 2021 se comunicaron 55.824 brotes con 414.882 casos en todos los ámbitos. Alrededor del 12,5% de brotes y casos asociados fueron comunicados en el ámbito laboral y dentro de éste, la mayoría se identificó en los sectores de la industria y construcción, si bien, entre los brotes que han tenido un mayor impacto se encuentran aquellos producidos en el sector agrícola y en la industria de la carne, donde existe un mayor riesgo de exposición debido a las condiciones de vida y trabajo. También destacaron los brotes en el sector de la restauración y hostelería, y cuidados a domicilio. Desde el inicio hubo una coordinación entre las administraciones implicadas en la gestión de la pandemia para poner en marcha las medidas de prevención y control, así como las de protección social. Además, se llevaron a cabo medidas especiales en sectores de mayor vulnerabilidad. A pesar del trabajo realizado, los brotes en estos sectores continúan ocurriendo, si bien son de menor tamaño, por lo que se deben continuar fortaleciendo las estructuras y mecanismos de coordinación intersectoriales para la aplicación de las medidas que contribuyen además de la contención de la pandemia, a mantener activo el tejido productivo.

[Monitoring and non pharmacologic measures during a pandemic virus (H1N1) 2009 in Spain]. / Bases epidemiológicas para la toma de decisiones sobre medidas de salud pública (no farmacológicas) durante la respuesta a la pandemia de gripe (H1N1) 2009.

Nonpharmacological public health measures are used to reduce exposure of susceptible persons to an infectious agent. Its use is recommended at the start of a pandemic, when the transmission begins, and the characteristics of the new virus are unknown. The National Plan for Preparedness and Response to Pandemic Influenza included the application of these measures, recommending the establishment of an Advisory Committee for implementation, with a multidisciplinary composition. The mandate at this Committee is to analyze the epidemiological and social context in confronting the pandemic and to propose public health measures according to their evolution. This article describes isolation, quarantine and closure of schools measures, aiming to reduce the spread of the virus in the population. It also reviews the epidemiological parameters that help to understand the impact of its implementation. The public health measures reviewed in this paper reduce transmission of the virus, and they have to be considered in response to an influenza pandemic. The impact on health will depend on how quickly they are taken and how people accept and follow them. Response plans should recommend its use, depending on the severity and characteristics of the new pandemic virus. The data analysis should be considered as part of the response, because the information collection and analysis will be key to advising health authorities on what measures should be adopted.

[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.

[Pandemic influenza (H1N1) 2009 Outbreak in a Military Academy: start of community circulation in Spain]. / Brote de gripe pandémica (H1N1) 2009 en una academia militar: inicio de la circulación comunitaria en España.

BACKGROUND: On May 19, 2009, 21 cases of influenza-like illness were reported among soldiers from an Engineering Military Academy (ACING) in Hoyo de Manzanares, Spain. In the context of an influenza A (H1N1)2009 global alert, it was decided to investigate a possible pandemic influenza outbreak. To describe a possible outbreak of influenza A (H1N1)2009 in a Military Training Centre and to describe the measures adopted for transmission control of this new infection. METHODS: A specific questionnaire was administered and biological samples were collected from all cases under investigation. Isolation and quarantine were recommended for cases and contacts, respectively. RESULTS: Eighty-one cases were confirmed. Among 52 samples tested, 31 were positive for influenza virus A/California/7/2009. The average age of the cases was 22.0 years (range 18-31 years) and 84% were men. Most common reported symptoms were cough and fever. All cases were isolated and treated with oseltamivir, with full recovery. The total attack rate was 12.42%. None of the cases had history of travel to risk areas or contact with previously diagnosed cases outside the academy. Thirty-one confirmed cases related to this outbreak were identified outside the academy, 24 cases were family contacts and friends. CONCLUSIONS: This outbreak was the first evidence of community transmission of pandemic influenza H1N1 in Spain. The rapid detection of this outbreak enhanced an early implementation of measures aiming at the containment of its transmission.

[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.