Severe Cases of Pandemic (H1N1) 2009 in Children | CDC EID

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Volume 17, Number 2–February 2011
Research
Severe Cases of Pandemic (H1N1) 2009 in Children, Germany
Mathias Altmann, Lena Fiebig, Jana Soyka, Rüdiger von Kries, Manuel Dehnert, and Walter Haas
Author affiliations: Robert Koch Institute, Berlin, Germany (M. Altmann, L. Fiebig, J. Soyka, M. Dehnert, W. Haas); and Ludwig-Maximilians-Universität, Munich, Germany (R. von Kries)
Suggested citation for this article

Abstract
In a hospital-based observational study in Germany, we investigated children admitted to pediatric intensive care units and deaths caused by confirmed pandemic (H1N1) 2009 to identify risk factors and outcomes in critically ill children. Ninety-three children were eligible for our study, including 9 with hospital-acquired infections. Seventy-five percent had underlying chronic medical conditions; neurodevelopmental disorders were most prevalent (57%). The proportion of patients having >1 risk factor increased with age in years (odds ratio 1.21, p = 0.007). Of 15 deaths, 11 occurred in a pediatric intensive care unit (case-fatality rate 12%, 95% confidence interval 6%–21%). Only 9% of the children had been vaccinated against pandemic (H1N1) 2009; all survived. Our results stress the role of underlying risk factors, especially neurodevelopmental disorders, and the need for improving preventive measures to reduce severe disease and adverse outcomes of pandemic (H1N1) 2009 in children.
The novel strain of influenza known as pandemic (H1N1) 2009 virus that originated in Mexico and the United States resulted in the first pandemic of the 21st century. Cases were observed in 214 countries, and 18,097 laboratory-confirmed deaths caused by this virus have been reported (1). In Germany, where the first cases were confirmed on April 29, 2009, the number of reported cases was 226,158 (including 255 deaths) as of May 18, 2010 (2).

Children were particularly affected by pandemic (H1N1) 2009. This finding is evident in the age distribution of patients, which is skewed toward younger age groups, and in high hospitalization rates for children identified in many settings worldwide (3–5). Severity has been mostly assessed in terms of admission to intensive care units (ICUs) and case-fatality rates. In a cohort study in Australia and New Zealand, the highest age-specific incidence rate for ICU admission was for children <1 year of age (6). Observational studies in ICU settings in the early pandemic phase in Mexico (7) and Canada (8) highlighted high rates of adolescents among critically ill patients. Studies conducted in pediatric ICU (PICU) settings originate predominantly from the Americas (9–11). In Europe, Lister et al. summarized experiences from 4 ICUs in the United Kingdom and identified 13 critically ill children with pandemic (H1N1) 2009 during June–July 2009 (12). These studies and national surveillance systems contributed to a better understanding of determinants and risk factors for severe disease in children. However, information from countries in Europe about severe cases of pandemic influenza (H1N1) 2009 in children who are particularly vulnerable is still limited (12,13). To obtain information on risk factors, course of disease, and outcome of critically ill children with pandemic (H1N1) 2009, we prospectively performed a nationwide observational study covering the fall wave of pandemic (H1N1) 2009 in Germany. full-text: Severe Cases of Pandemic (H1N1) 2009 in Children | CDC EID


Suggested Citation for this Article
Altmann M, Fiebig L, Soyka J, von Kries R, Dehnert M, Haas W. Severe cases of pandemic (H1N1) 2009 in children, Germany. Emerg Infect Dis [serial on the Internet]. 2011 Feb [date cited]. http://www.cdc.gov/EID/content/17/2/186.htm

DOI: 10.3201/eid1702.101090


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Mathias Altmann, Department for Infectious Disease Epidemiology, Respiratory Infections Unit, Robert Koch Institute, Postfach 65 02 61, 13302 Berlin, Germany; email: altmannm@rki.de