Comparative Characteristics of the 2009 Pandemic Influenza A (H1N1) Virus and 2010-2011 Seasonal Influenza in Pediatric Patients.

BACKGROUND: In March 2009 the pandemic influenza A (H1N1) strain was identified. The disease initially appeared to be accompanied by complications and high mortality rates. It became an endemic virus during the influenza season in our region, along with the classical seasonal H3N2. OBJECTIVES: To identify the burden of pandemic influenza, its effect in pediatric patients, and complicated hospitalizations, compared to seasonal influenza years after the pandemic. METHODS: A retrospective observational study was conducted at a tertiary hospital. Data were collected from the medical records of all children who were hospitalized from April 2009 to 2011 with laboratory-confirmed influenza. RESULTS: Of 191 patients with influenza, 100 had the 2009 pandemic influenza, 62 had seasonal influenza, and 29 had H1N1 in 2010-2011. Patients with the 2009 H1N1 were characterized by older age, more co-morbidity conditions and more symptoms including fever, cough and rhinitis on admission. No significant differences in outcomes between the groups were recorded. Of patients hospitalized with pandemic influenza in 2009, 28% had complicated hospitalizations, compared with 17.7% of patients hospitalized with seasonal influenza in 2010-11. Children with pandemic influenza received more oseltamivir (Tamiflu®) (94% vs. 19.4%, P < 0.001) and more antibiotics than the other groups. CONCLUSIONS: The type of influenza had no effect on outcome. There were no significant differences between groups in the percentages of in-hospital mortality, admission to intensive care units, prolonged hospitalization (> 9 days), or the development of complications during hospitalization.

Bronchiectasis with Chronic Rhinosinusitis Is Associated with Eosinophilic Airway Inflammation and Is Distinct from Asthma.

Rationale: Bronchiectasis is an airway inflammatory disease that is frequently associated with chronic rhinosinusitis (CRS). An eosinophilic endotype of bronchiectasis has recently been described, but detailed testing to differentiate eosinophilic bronchiectasis from asthma has not been performed. Objectives: This prospective observational study aimed to test the hypotheses that bronchiectasis with CRS is enriched for the eosinophilic phenotype in comparison with bronchiectasis alone and that the eosinophilic bronchiectasis phenotype exists as a separate entity from bronchiectasis associated with asthma. Methods: People with idiopathic or postinfectious bronchiectasis were assessed for concomitant CRS. We excluded people with asthma or primary ciliary dyskinesia and smokers. We assessed sputum and blood cell counts, nasal NO and fractional excreted NO, methacholine reactivity, skin allergy testing and total and specific immunoglobulin (Ig) E, cytokines in the sputum and serum, and the microbiome in the sputum and nasopharynx. Results: A total of 22 people with CRS (BE + CRS) and 17 without CRS (BE - CRS) were included. Sex, age, Reiff score, and bronchiectasis severity were similar. Median sputum eosinophil percentages were 0% (IQR, 0-1.5%) in BE - CRS and 3% (1-12%) in BE + CRS (P = 0.012). Blood eosinophil counts were predictive of sputum eosinophilia (counts ⩾3%; area under the receiver operating characteristic curve, 0.68; 95% confidence interval, 0.50-0.85). Inclusion of CRS improved the prediction of sputum eosinophilia by blood eosinophil counts (area under the receiver operating characteristic curve, 0.79; 95% confidence interval, 0.65-0.94). Methacholine tests were negative in 85.7% of patients in the BE - CRS group and 85.2% of patients in the BE + CRS group (P > 0.99). Specific IgE and skin testing were similar between the groups, but total IgE levels were increased in people with increased sputum eosinophils. Microbiome analysis demonstrated distinct microbiota in nasopharyngeal and airway samples in the BE + CRS and BE - CRS groups, without significant differences between groups. However, interactome analysis revealed altered interactomes in individuals with high sputum eosinophil counts and CRS. Conclusions: Bronchiectasis with CRS is associated with an eosinophilic airway inflammation that is distinct from asthma.