The clinical and health economic burden of respiratory syncytial virus disease among children under 2 years of age in a defined geographical area.
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AIMS: To describe the clinical and health economic impact of respiratory syncytial virus (RSV) disease in children under 2 years of age. METHODS: Hospitalised children less than 2 years of age with a respiratory illness were studied over three consecutive RSV seasons (1996-99). RESULTS: The rates (per 1000 infants under 1 year of age) of hospitalisations from bronchiolitis and RSV illness were 30.8 and 24.4 respectively. The rates of death, intensive care admission, and need for ventilatory assistance during RSV related hospitalisation were 0.2%, 2.7%, and 1.5% respectively. From a cohort of 841 preterm infants, 6.3% had an RSV related hospitalisation during the study period, with the rate rising to 9.2% among those who were either born before 36 weeks gestation and were under 6 months of age at the onset of the RSV seasons, or were less than 2 years of age with chronic lung disease needing home oxygen therapy. Eight of 25 children on home oxygen therapy had RSV related rehospitalisation. Need for assisted ventilation during the neonatal period and discharge home on oxygen therapy were significantly associated with the risk of subsequent RSV related hospitalisation in preterm infants less than 6 months of age. The direct health authority cost of all RSV hospitalisations was pound 542 203, while the currently recommended immunoprophylaxis for the high risk infants would have cost pound 652 960. CONCLUSIONS: Preterm infants receiving assisted ventilation and those on home oxygen therapy are particularly at risk of RSV related hospitalisation. Serious adverse outcomes are however uncommon even among these high risk infants. (+info)
Pro- and anti-inflammatory responses in respiratory syncytial virus bronchiolitis.
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Respiratory syncytial virus (RSV) bronchiolitis is an important cause of severe respiratory disease in infants. This study aimed to characterise changes in pulmonary pro- and anti-inflammatory responses in infants with RSV bronchiolitis over the course of the illness. On the day of intubation (Day 1) and the day of extubation (Day X), nonbronchoscopic bronchoalveolar lavage was performed on term and preterm infants ventilated for RSV bronchiolitis and on control infants on Day 1. Tumour necrosis factor (TNF)-alpha, soluble TNF receptor (sTNFR) and interleukin (IL)-6 messenger ribonucleic acid (mRNA) and protein were measured. Twenty-four infants, born at term and 23 infants born preterm with RSV bronchiolitis and 10 controls were recruited. TNF-alpha and IL-6 mRNA and protein in infants with bronchiolitis were greater than the control group on Day 1. In preterm infants, who were ventilated for longer than term infants, TNF-alpha and IL-6 proteins decreased between Day 1 and Day X. Concentrations of sTNFRs differed between groups on Day 1, but levels did not change between Day 1 and Day X. Large amounts of tumour necrosis factor-alpha and interleukin-6 in the respiratory syncytial virus-infected lung suggest important roles for these cytokines in the pathogenesis of respiratory syncytial virus bronchiolitis. The decrease in tumour necrosis factor-alpha and interleukin-6 protein in preterm infants may reflect the prolonged clinical course seen in these infants. (+info)
Treating acute bronchiolitis associated with RSV.
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Treatment for infants with bronchiolitis caused by respiratory syncytial virus (RSV) includes supplemental oxygen, nasal suctioning, fluids to prevent dehydration, and other supportive therapies. High-risk children who should be hospitalized include those younger than three months and those with a preterm birth, cardiopulmonary disease, immunodeficiency, respiratory distress, or inadequate oxygenation. Inhaled beta2-agonist bronchodilators, the anticholinergic agent ipratropium bromide, and nebulized epinephrine have not been shown to be effective for treating RSV bronchiolitis. However, the Agency for Healthcare Research and Quality states that nebulized epinephrine and nebulized ipratropium bromide are possibly effective. The appropriate use of corticosteroids remains controversial. They may provide some benefit but meta-analyses of clinical trial results are inconsistent. Prophylaxis with RSV intravenous immune globulin or palivizumab, a human monoclonal antibody, can reduce hospitalization rates in high-risk patients, although difficulties with administering the medications and high costs may preclude their widespread use. The use of common infection-control measures can reduce nosocomial transmission of RSV infections. (+info)
Respiratory viruses detected in hospitalised paediatric patients with respiratory infections.
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Over 200 strains of respiratory viruses cause a variety of human infections ranging from common cold to life-threatening pneumonia. Respiratory viruses implicated in this study are respiratory syncytial viruses (RSV), adenovirus, influenza viruses and parainfluenza viruses. The objective of this study is to determine the epidemiology of respiratory viruses in paediatric patients with lower respiratory tract infection. The methods used were direct antigen detection method, shell vial culture method and conventional tube culture method. The samples included in this study are paediatric patients seen in Universiti Kebangsaan Malaysia Hospital, Kuala Lumpur with suspected acute viral respiratory infection, presenting with acute laryngotracheobronchitis (croup), bronchiolitis and pneumonia. Nasopharyngeal aspirates were collected and processed almost immediately. A total of 222 specimens were received during February 1999 to January 2000 showing a dual peak pattern in the months of April and December. The mean age of the patients was 13 months. Pneumonia (77.9%) was the most common clinical diagnosis in children with lower respiratory tract infection. This was followed by bronchiolitis (19.4%) and croup (27%). Viral aetiologies were confirmed in 23.4% of the patients. The most common respiratory virus isolated or detected was RSV, followed by parainfluenza viruses, influenza viruses and adenovirus. (+info)
IL-12p40 and IL-18 modulate inflammatory and immune responses to respiratory syncytial virus infection.
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Respiratory syncytial virus-induced bronchiolitis has been linked to the development of allergy and atopic asthma. IL-12 and possibly IL-18 are central mediators orchestrating Th1 and/or Th2 immune responses to infection. To determine a possible role for IL-12 in regulating the immune response to acute respiratory syncytial virus infection, IL-12p40 gene-targeted (IL-12p40-/-) and wild-type mice were intratracheally infected with respiratory syncytial virus, and lung inflammatory and immune responses were assessed. Lung inflammation and mucus production were increased in the airways of IL-12p40-/- mice as compared with those of wild-type mice, concurrent with increased levels of the Th2 effector cytokines IL-5 and IL-13. Respiratory syncytial virus clearance and levels of Th1 effector cytokine IFN-gamma were not altered. Interestingly, IL-18, another mediator of IFN-gamma production, was significantly increased in the lungs of IL-12p40-/- mice early during the course of infection. Abrogation of IL-18-mediated signaling in IL-12p40-/- mice further enhanced Th2 immune response and mucus production in the airways during respiratory syncytial virus infection but failed to modulate IFN-gamma production or viral clearance. These findings implicate a role for IL-12 and IL-18 in modulating respiratory syncytial virus-induced airway inflammation distinct from that of viral clearance. (+info)
Resolution of primary severe acute respiratory syndrome-associated coronavirus infection requires Stat1.
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Intranasal inhalation of the severe acute respiratory syndrome coronavirus (SARS CoV) in the immunocompetent mouse strain 129SvEv resulted in infection of conducting airway epithelial cells followed by rapid clearance of virus from the lungs and the development of self-limited bronchiolitis. Animals resistant to the effects of interferons by virtue of a deficiency in Stat1 demonstrated a markedly different course following intranasal inhalation of SARS CoV, one characterized by replication of virus in lungs and progressively worsening pulmonary disease with inflammation of small airways and alveoli and systemic spread of the virus to livers and spleens. (+info)
Pulmonary and systemic bacterial co-infections in severe RSV bronchiolitis.
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In 127 infants admitted to intensive care for RSV bronchiolitis, concomitant bacterial sepsis was a rare event. However, in the subgroup of intubated patients the incidence of bacterial pneumonia was 43.9% (95% CI 31.0-56.8%), half community acquired and half nosocomial. As clinical signs are not helpful in identifying these patients, tracheal aspirates have to be investigated microbiologically on a routine basis in order to start antibiotics in time. (+info)
Hospitalisations for respiratory syncytial virus bronchiolitis in Akershus, Norway, 1993-2000: a population-based retrospective study.
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BACKGROUND: RSV is recognized as the most important cause of serious lower respiratory tract illness in infants and young children worldwide leading to hospitalisation in a great number of cases, especially in certain high-risk groups. The aims of the present study were to identify risk groups, outcome and incidences of hospitalisation for RSV bronchiolitis in Norwegian children under two years of age and to compare the results with other studies. METHODS: We performed a population-based retrospective survey for the period 1993-2000 in children under two years of age hospitalised for RSV bronchiolitis. RESULTS: 822 admissions from 764 patients were identified, 93% had one hospitalisation, while 7% had two or more hospitalisations. Mean annual hospitalisation incidences were 21.7 per 1.000 children under one year of age, 6.8 per 1.000 children at 1-2 years of age and 14.1 per 1.000 children under two years of age. 77 children (85 admissions) belonged to one or more high-risk groups such as preterm birth, trisomy 21 and congenital heart disease. For preterm children under one year of age, at 1-2 years of age and under two years of age hospitalisation incidences per 1.000 children were 23.5, 8.7 and 16.2 respectively. The incidence for children under two years of age with trisomy 21 was 153.8 per 1.000 children. CONCLUSION: While the overall hospitalisation incidences and outcome of RSV bronchiolitis were in agreement with other studies, hospitalisation incidences for preterm children were lower than in many other studies. Age on admission for preterm children, when corrected for prematurity, was comparable to low-risk children. Length of hospitalisation and morbidity was high in both preterm children, children with a congenital heart disease and in children with trisomy 21, the last group being at particular high risk for severe disease. (+info)