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Pandemic A/H1N1v influenza 2009 in hospitalized children: a multicenter Belgian survey

Sophie Blumental1*, Elisabeth Huisman2, Marie-Coralie Cornet3, Christine Ferreiro4, Iris De Schutter2, Marijke Reynders5, Ingrid Wybo6, Benoît Kabamba-Mukadi7, Ruth Armano3, Dominique Hermans3, Marie-Cécile Nassogne3, Bhavna Mahadeb8, Christine Fonteyne9, Gerlant Van Berlaer10, Jack Levy4, Didier Moulin3, Anne Vergison111, Anne Malfroot2 and Philippe Lepage1

Author Affiliations

1 Pediatric Infectious Diseases Unit, Hôpital Universitaire des Enfants Reine Fabiola (HUDERF), Brussels, Belgium

2 Pediatric Pneumology and Infectious Diseases Department, Universitair Ziekenhuis Brussel (UZB), Brussels, Belgium

3 Department of Pediatrics, Cliniques Universitaires St-Luc (UCLouvain), Brussels, Belgium

4 Department of Pediatrics, Hôpital Universitaire St-Pierre, Brussels, Belgium

5 Microbiology Unit, Hôpital Universitaire St-Pierre, Brussels, Belgium

6 Microbiology Unit, UZB, Brussels, Belgium

7 Microbiology Unit, UCLouvain, Brussels, Belgium

8 Department of Pediatrics, HUDERF, Brussels, Belgium

9 Intensive Care Unit, HUDERF, Brussels, Belgium

10 Emergency and Intensive Care Unit, UZB, Brussels, Belgium

11 Infection Control Unit, HUDERF, Brussels, Belgium

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BMC Infectious Diseases 2011, 11:313  doi:10.1186/1471-2334-11-313

Published: 7 November 2011



During the 2009 influenza A/H1N1v pandemic, children were identified as a specific "at risk" group. We conducted a multicentric study to describe pattern of influenza A/H1N1v infection among hospitalized children in Brussels, Belgium.


From July 1, 2009, to January 31, 2010, we collected epidemiological and clinical data of all proven (positive H1N1v PCR) and probable (positive influenza A antigen or culture) pediatric cases of influenza A/H1N1v infections, hospitalized in four tertiary centers.


During the epidemic period, an excess of 18% of pediatric outpatients and emergency department visits was registered. 215 children were hospitalized with proven/probable influenza A/H1N1v infection. Median age was 31 months. 47% had ≥ 1 comorbid conditions. Febrile respiratory illness was the most common presentation. 36% presented with initial gastrointestinal symptoms and 10% with neurological manifestations. 34% had pneumonia. Only 24% of the patients received oseltamivir but 57% received antibiotics. 10% of children were admitted to PICU, seven of whom with ARDS. Case fatality-rate was 5/215 (2%), concerning only children suffering from chronic neurological disorders. Children over 2 years of age showed a higher propensity to be admitted to PICU (16% vs 1%, p = 0.002) and a higher mortality rate (4% vs 0%, p = 0.06). Infants less than 3 months old showed a milder course of infection, with few respiratory and neurological complications.


Although influenza A/H1N1v infections were generally self-limited, pediatric burden of disease was significant. Compared to other countries experiencing different health care systems, our Belgian cohort was younger and received less frequently antiviral therapy; disease course and mortality were however similar.