Incidence of viral respiratory infections in a prospective cohort of outpatient and hospitalized children aged ≤5 years and its associated cost in Buenos Aires, Argentina.

BACKGROUND: Although information about the incidence of viral respiratory illnesses and their associated cost can help health officials explore the value of interventions, data are limited from middle-income countries. METHODS: During 2008-2010, we conducted a prospective cohort study and followed ~1,800 Argentinian children aged ≤5 years to identify those children who were hospitalized or who sought care at an emergency room with any acute respiratory infection sign or symptom (e.g., rhinorrhea, cough, wheezing, tachypnea, retractions, or cyanosis). Respiratory samples were obtained for respiratory syncytial virus, influenza, parainfluenza, adenovirus, and metapneumovirus testing by immunofluorescence and for rhinovirus by real-time reverse transcription polymerase chain reaction. RESULTS: The incidence of respiratory syncytial virus (24/1000 children-years), human metapneumovirus (8/1000 children-years), and influenza (8/1000 children-years) illnesses was highest among hospitalized children aged <6 months and decreased among older children. In contrast, the incidence of rhinovirus was highest (12/1000 children-years) among those aged 6-23 months. In the emergency room, the incidence of rhinovirus was 459; respiratory syncytial virus 352; influenza 185; parainfluenza 177; metapneumovirus 130; and adenovirus 73/1,000 children-years. The total cost of hospitalization was a median of US$529 (Interquartile range, US$362-789). CONCLUSIONS: Our findings indicate that respiratory viruses, in particular rhinovirus, respiratory syncytial virus, metapneumovirus, and influenza may be associated with severe illness causing substantial economic burden.

Viral etiology of acute respiratory infections in hospitalized and outpatient children in Buenos Aires, Argentina.

OBJECTIVES: To determine and compare the viral frequency, seasonality and clinical-demographic features in 2 groups of children (hospitalized versus outpatients) with acute respiratory infections. MATERIAL AND METHODS: A cross-sectional, descriptive study was performed from 2008 to 2010 in 620 children <6 years of age with acute respiratory infection. Respiratory samples were studied for classical respiratory viruses by immunofluorescence and for human rhinoviruses (HRV) by real-time reverse transcription polymerase chain reaction. Clinical and demographic data were recorded. RESULTS: Viral detection by immunofluorescence was 48% in 434 inpatients and 37% in 186 outpatients. Viral diagnosis increased to 83% and 62%, respectively, when testing for HRV. HRV (41%) and respiratory syncytial virus (RSV) (27%) were most common viruses identified, followed by metapneumovirus (9%), influenza A and parainfluenza (3%), adenovirus and influenza B (2%). HRV frequency was significantly higher in hospitalized patients (47%) than in outpatients (27%) (P < 0.001). Coinfection was detected in 12% of hospitalized and 4% of outpatients (P < 0.031). HRV and adenovirus circulated throughout the entire year. RSV, influenza A and B predominated in winter, whereas metapneumovirus and parainfluenza predominated in spring. Of 362 patients with bronchiolitis, 84% had a virus identified; HRV (42%) and RSV (38%) were predominant. Of 77 patients with pneumonia, 84% had a virus detected with HRV (43%) and RSV (29%) predominating. CONCLUSIONS: HRV were significant pathogens associated with bronchiolitis and pneumonia, especially in hospitalized patients. Both, HRV and coinfections, were risk factors for hospitalization. These findings support the importance of including HRV detection in children with acute respiratory infection.

Rinovirus: Frecuencia en niños con infección respiratoria aguda, no internados / Rhinoviruses: Frequency in nonhospitalized children with acute respiratory infection

Los métodos moleculares para diagnosticar rinovirus humanos (RVH) han aumentado la sensibilidad de detección. Esto ha permitido documentar la asociación entre los RVH y las infecciones respiratorias agudas (IRA) altas y bajas. La infección por RVH durante la infancia se asoció con posterior desarrollo de asma. Se estudió la frecuencia de RVH en 186 niños menores de 6 años ambulatorios con IRA (alta o baja), durante 2 años consecutivos (1/6/2008 - 31/5/2010). Se correlacionó la presencia de RVH con los antecedentes y características clínico-epidemiológicas. La detección de RVH se realizó con una RT-PCR en tiempo real que amplifica parte de la región 5' no codificante del genoma. Los virus respiratorios clásicos se estudiaron por inmunofluorescencia. En el 61% de los niños se detectó etiología viral. Las frecuencias fueron: RVH 27%, virus sincicial respiratorio (VSR) 16%, influenza A y B 9%, parainfluenza 8%, metapneumovirus 7% y adenovirus 0.5%. Se observaron coinfecciones duales en 8 casos, siendo RVH el más frecuente (en 4 de ellos). Los RVH circularon durante todo el período estudiado, con picos en invierno y primavera. No se observaron diferencias clínico-epidemiológicas significativas entre pacientes con o sin RVH, excepto un mayor porcentaje de niños afebriles con RVH. Los RVH fueron los virus más detectados en niños ambulatorios, principalmente en menores de 2 años, los segundos virus asociados a bronquiolitis, luego del VSR, y detectados tres veces más en los niños expuestos a tabaquismo pasivo (OR: 2,91; p = 0.012) que en el resto. Fueron identificados como único agente en el 28% de las bronquiolitis.

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5' non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.

Rinovirus: Frecuencia en niños con infección respiratoria aguda, no internados / Rhinoviruses: Frequency in nonhospitalized children with acute respiratory infection

Los métodos moleculares para diagnosticar rinovirus humanos (RVH) han aumentado la sensibilidad de detección. Esto ha permitido documentar la asociación entre los RVH y las infecciones respiratorias agudas (IRA) altas y bajas. La infección por RVH durante la infancia se asoció con posterior desarrollo de asma. Se estudió la frecuencia de RVH en 186 niños menores de 6 años ambulatorios con IRA (alta o baja), durante 2 años consecutivos (1/6/2008 - 31/5/2010). Se correlacionó la presencia de RVH con los antecedentes y características clínico-epidemiológicas. La detección de RVH se realizó con una RT-PCR en tiempo real que amplifica parte de la región 5 no codificante del genoma. Los virus respiratorios clásicos se estudiaron por inmunofluorescencia. En el 61% de los niños se detectó etiología viral. Las frecuencias fueron: RVH 27%, virus sincicial respiratorio (VSR) 16%, influenza A y B 9%, parainfluenza 8%, metapneumovirus 7% y adenovirus 0.5%. Se observaron coinfecciones duales en 8 casos, siendo RVH el más frecuente (en 4 de ellos). Los RVH circularon durante todo el período estudiado, con picos en invierno y primavera. No se observaron diferencias clínico-epidemiológicas significativas entre pacientes con o sin RVH, excepto un mayor porcentaje de niños afebriles con RVH. Los RVH fueron los virus más detectados en niños ambulatorios, principalmente en menores de 2 años, los segundos virus asociados a bronquiolitis, luego del VSR, y detectados tres veces más en los niños expuestos a tabaquismo pasivo (OR: 2,91; p = 0.012) que en el resto. Fueron identificados como único agente en el 28% de las bronquiolitis.(AU)

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5 non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.(AU)

Rinovirus: Frecuencia en niños con infección respiratoria aguda, no internados / Rhinoviruses: Frequency in nonhospitalized children with acute respiratory infection

Los métodos moleculares para diagnosticar rinovirus humanos (RVH) han aumentado la sensibilidad de detección. Esto ha permitido documentar la asociación entre los RVH y las infecciones respiratorias agudas (IRA) altas y bajas. La infección por RVH durante la infancia se asoció con posterior desarrollo de asma. Se estudió la frecuencia de RVH en 186 niños menores de 6 años ambulatorios con IRA (alta o baja), durante 2 años consecutivos (1/6/2008 - 31/5/2010). Se correlacionó la presencia de RVH con los antecedentes y características clínico-epidemiológicas. La detección de RVH se realizó con una RT-PCR en tiempo real que amplifica parte de la región 5 no codificante del genoma. Los virus respiratorios clásicos se estudiaron por inmunofluorescencia. En el 61% de los niños se detectó etiología viral. Las frecuencias fueron: RVH 27%, virus sincicial respiratorio (VSR) 16%, influenza A y B 9%, parainfluenza 8%, metapneumovirus 7% y adenovirus 0.5%. Se observaron coinfecciones duales en 8 casos, siendo RVH el más frecuente (en 4 de ellos). Los RVH circularon durante todo el período estudiado, con picos en invierno y primavera. No se observaron diferencias clínico-epidemiológicas significativas entre pacientes con o sin RVH, excepto un mayor porcentaje de niños afebriles con RVH. Los RVH fueron los virus más detectados en niños ambulatorios, principalmente en menores de 2 años, los segundos virus asociados a bronquiolitis, luego del VSR, y detectados tres veces más en los niños expuestos a tabaquismo pasivo (OR: 2,91; p = 0.012) que en el resto. Fueron identificados como único agente en el 28% de las bronquiolitis.(AU)

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5 non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.(AU)

[Rhinoviruses. Frequency in nonhospitalized children with acute respiratory infection]. / Rinovirus. Frecuencia en niños con infección respiratoria aguda, no internados.

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5' non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.

[Acute viral respiratory infection in children under 5 years: Epidemiological study in two centers in Buenos Aires, Argentina]. / Infección respiratoria aguda viral en niños menores de 5 años: Estudio epidemiológico en dos centros de Buenos Aires, Argentina.

INTRODUCTION: Acute respiratory infections (ARI) are a major cause of hospitalization particularly at the extreme ages of life. OBJECTIVES: To determine the viral diagnosis in children < 5 years old with ARI, seasonality, clinical and epidemiological characteristics. POPULATION AND METHODS: A cross-sectional, descriptive and multicenter study was performed. Respiratory samples from patients with ARI hospitalized or outpatients with < 5 days of respiratory symptoms from June 2008 to May 2009 were studied for respiratory viruses. Clinical and demographic data were recorded. RESULTS: A total of 347 patients were enrolled: 234 hospitalized and 112 outpatients. Hospitalized patients were younger compared with outpatients (8 vs. 19 months, p <0.001) and presented more frequently bronchiolitis (74% hospitalized vs. 24% outpatients) and pneumonia (14% hospitalized vs. 5% outpatients). Age was statistically associated with hospitalization (p= 0.01). Viral diagnosis was achieved in 81% hospitalized and 57% of outpatients. Rhinovirus was the most frequent followed by respiratory syncytial virus. The rest of respiratory viruses were observed with lower frequency. Viral circulation was observed throughout the whole year. The median length of stay was 3.5 days. Intensive care was required in 11% of hospitalized patients and 3% required mechanical ventilation. No deaths were recorded. CONCLUSIONS: The use of viral diagnostic techniques allowed the identification of an etiologic agent in most of the hospitalized patients and more than half of outpatients. The addition of RT-PCR for rhinovirus, allowed the identification of this etiologic agent. Viral circulation was observed throughout the whole year. Hospitalized patients presented bronchiolitis and pneumonia more frequently than outpatients.

Infección respiratoria aguda viral en niños menores de 5 años: Estudio epidemiológico en dos centros de Buenos Aires, Argentina / Acute viral respiratory infection in children under 5 years: Epidemiological study in two centers in Buenos Aires, Argentina

Introducción. Las infecciones respiratorias agudas (IRA) son la mayor causa de hospitalización en edades extremas de la vida. Objetivos. Identifcar los agentes etiológicos de IRA viral en niños < 5 años hospitalizados y ambulatorios; describir estacionalidad y características clínico-epidemiológicas de la enfermedad. Población y métodos. Estudio descriptivo, transversal y multicéntrico en dos centros privados de Buenos Aires, en niños con IRA alta y baja. Se registraron antecedentes, cuadros clínicos y estudios virológicos. Resultados. Se estudiaron 347 pacientes: 235 hospitalizados; 112 ambulatorios. Los hospitalizados fueron menores que los ambulatorios (8 vs. 19 meses, p <0,001), presentaron más frecuentemente bronquiolitis (74% hospitalizados vs. 24% ambulatorios) y neumonía (14% hospitalizados vs. 5% ambulatorios). Solo la edad se asoció signifcativamente a hospitalización (p= 0,01). Se identifcó etiología viral en 81% de los hospitalizados y 57% de los ambulatorios. El virus más frecuente fue rinovirus seguido por virus respiratorio sincicial. Se observó circulación viral durante todo el año, especialmente en otoño e invierno. En pacientes hospitalizados, la mediana de hospitalización fue 3,5 días. Requirieron cuidados intensivos 25 (11%) pacientes, y 7 (3%) recibieron asistencia ventilatoria mecánica. No hubo letalidad. Conclusiones. Las técnicas de diagnóstico virológico permitieron identifcar agentes etiológicos en la mayoría de los pacientes hospitalizados y en más de la mitad de los ambulatorios con IRA. La incorporación de RT-PCR para rinovirus, permitió la identifcación de este agente etiológico. La circulación viral se observó a lo largo de todo el año. La bronquiolitis fue causa de internación en 174/201 (86,5%) niños con IRA y la neumonía en 33/39 (84,6%) niños.

Introduction. Acute respiratory infections (ARI) are a major cause of hospitalization particularly at the extreme ages of life. Objectives. To determine the viral diagnosis in children < 5 years old with ARI, seasonality, clinical and epidemiological characteristics. Population and methods. A cross-sectional, descriptive and multicenter study was performed. Respiratory samples from patients with ARI hospitalized or outpatients with < 5 days of respiratory symptoms from June 2008 to May 2009 were studied for respiratory viruses. Clinical and demographic data were recorded. Results. A total of 347 patients were enrolled: 234 hospitalized and 112 outpatients. Hospitalized patients were younger compared with outpatients (8 vs. 19 months, p <0.001) and presented more frequently bronchiolitis (74% hospitalized vs. 24% outpatients) and pneumonia (14% hospitalized vs. 5% outpatients). Age was statistically associated with hospitalization (p= 0.01). Viral diagnosis was achieved in 81% hospitalized and 57% of outpatients. Rhinovirus was the most frequent followed by respiratory syncytial virus. The rest of respiratory viruses were observed with lower frequency. Viral circulation was observed throughout the whole year. The median length of stay was 3.5 days. Intensive care was required in 11% of hospitalized patients and 3% required mechanical ventilation. No deaths were recorded. Conclusions. The use of viral diagnostic techniques allowed the identifcation of an etiologic agent in most of the hospitalized patients and more than half of outpatients. The addition of RT-PCR for rhinovirus, allowed the identifcation of this etiologic agent. Viral circulation was observed throughout the whole year. Hospitalized patients presented bronchiolitis and pneumonia more frequently than outpatients.