Pandemic influenza A vs seasonal influenza A in hospitalized children in Athens.

BACKGROUND: Data on pandemic H1N1 influenza (pH1N1) virus infection in hospitalised children are limited. AIMS AND OBJECTIVES: To examine the epidemiological and clinical characteristics of children hospitalised with pH1N1 at a large tertiary-care centre in Athens and compare them with those of children hospitalised with seasonal influenza A in previous years. METHODS: All children (n = 146) admitted with confirmed pH1N1 between October 2009 to February 2010 and January 2011 to May 2011 were included. Data on children ≧ 6 months of age (n = 109) were compared with those of 138 children admitted with seasonal influenza A who were examined during two previous influenza seasons (2002-2003 and 2004-2005). RESULTS: The age distribution was similar between seasonal and pandemic H1N1. Bronchial asthma was significantly more common in the seasonal influenza group but the clinical presentation was similar in the two groups, except that fever was more common in patients with pH1N1. Children admitted with seasonal influenza were more likely to develop acute otitis media. There were no significant differences between the two groups for severe outcomes (admission to the ICU, mechanical ventilation or death). Only one child with seasonal influenza (0.6%) and three with pH1N1 influenza (2%) required admission to the ICU. Mean length of hospitalisation was longer in the seasonal influenza group. CONCLUSION: Clinical manifestations were similar between pH1N1 and seasonal influenza, and the pandemic virus did not appear to cause more severe disease in hospitalised children.

Impact of influenza infection in healthy children examined as outpatients and their families.

Decisions regarding the introduction of influenza immunization in healthy children require an accurate evaluation of influenza disease burden not only in the inpatient but also in the outpatient setting. We prospectively examined the impact of virologically confirmed influenza in 1462 outpatient children (> or = 6 months to < 14 years) and their families, during two consecutive influenza seasons. Influenza was documented in 573/1462 (39%) outpatients with febrile respiratory illness and accounted for 13.5% of all outpatient visits during the 14 weeks of each season. Acute otitis media (AOM) was the most common complication (18.5%) and about 40% of influenza positive patients received antibiotics. AOM and antibiotic use were more common in children younger than 5 years of age who accounted for 58% of all patients. For each child sick with influenza a mean of 1.34 workdays were lost by the parents. Family members of influenza positive children were more likely to develop a secondary respiratory illness and to require medical visits and antibiotic prescriptions. Influenza is associated with a heavy morbidity burden in the community that may be reduced considerably with the implementation of immunization in children younger than 5 years of age.