Pandemic influenza A (H1N1v) infection in pediatric population: a multicenter study in a north-east area of Italy

BACKGROUND: Data on clinical presentation, morbidity and mortality of 2009 pandemic influenza virus (H1N1v) in paediatric population are still emerging; most of the data so far available came from selected cohorts of children admitted to tertiary care paediatric hospitals. METHODS: An observational study involving all the 19 Divisions of Paediatrics of the Veneto Region was conducted with the aim of investigating into the demographic and clinical characteristics, the treatment, the outcome and the risk factors for disease severity of H1N1v infection occurring in children. RESULTS: Two hundred children, median age of 4.15 years (range 0-15) were enrolled from the last week of October till the first week of January 2010 for an overall hospitalization rate of 23/100,000. At least one underlying medical condition was found in 44% of patients. Fever and cough were the most frequent symptoms (93% and 65% respectively). 11 patients (6%) were admitted to a PICU and 5 (2.5%) required mechanical ventilation. Antiviral therapy was administered in 103 patients (51.5%) Death occurred in 2 patients (1%); both had severe prior medical conditions. Pre-existing neurologic diseases (OR 7.82; 95%CI: 1.15-53.34), the presence of hypoxemia (OR 10.47; 95%CI: 2.12-51.70) and anemia (Haemoglobin < 10 g/dL) (OR 14.15; 95%CI: 2.36-84.64) were risk factor for Intensive Care Unit admission. CONCLUSIONS: This observational study in a given area of North-East Italy confirms the rather favourable prognosis of children with influenza A H1N1 (2009). Pre-existing conditions, and which is new, significant anemia, are risk factors for a complicated course.