Mortality of 2009 pandemic influenza A(H1N1) in Germany.

The mortality in Germany caused by the 2009 pandemic influenza A(H1N1) seems to have been one of the lowest in Europe. We provide a detailed analysis of all 252 fatal cases of confirmed infection with the pandemic virus notified between 29 April 2009 and 31 March 2010. The overall mortality was 3.1 (95% confidence interval (CI): 2.7 to 3.5) per one million inhabitants. We observed an increase in the case fatality rate of notified cases over time; notified cases aged 60 years or older had the highest case fatality rate (2.16%; 95% CI: 1.61 to 2.83; odds ratio: 5.4; p<0.001; reference group: 35–59 years). The median delay of four days (interquartile range (IQR): 2–7) between symptom onset and antiviral treatment was significantly longer in fatal cases than for non-fatal cases (median: two days (IQR: 1–3; p<0.001). Analysis of the underlying medical conditions of fatal cases, based on the observed frequency of the conditions in the general population, confirms the risk for fatal outcome, which is most notably due to immunosuppression, diabetes and respiratory diseases. Our results suggest that early treatment might have had an impact on overall mortality. Identification of risk groups for targeted intervention to prevent fatalities needs to take into account the distribution of underlying conditions in the population.

[1]  M. Biggerstaff,et al.  H1N1 2009 Influenza Virus Infection During Pregnancy in the United States , 2010 .

[2]  A. Gilsdorf,et al.  The first wave of pandemic influenza (H1N1) 2009 in Germany: From initiation to acceleration , 2010, BMC infectious diseases.

[3]  A. Charlett,et al.  Pandemic Influenza A (H1N1) 2009 and mortality in the United Kingdom: risk factors for death, April 2009 to March 2010. , 2010, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[4]  N. Andrews,et al.  Incidence of 2009 pandemic influenza A H1N1 infection in England: a cross-sectional serological study , 2010, The Lancet.

[5]  A. Fowlkes,et al.  Morbid Obesity as a Risk Factor for Hospitalization and Death Due to 2009 Pandemic Influenza A(H1N1) Disease , 2010, PloS one.

[6]  M. Honein,et al.  Severe 2009 H1N1 influenza in pregnant and postpartum women in California. , 2010, The New England journal of medicine.

[7]  Víctor Hugo Borja-Aburto,et al.  Infection and death from influenza A H1N1 virus in Mexico: a retrospective analysis , 2009, The Lancet.

[8]  Oliver T Mytton,et al.  Mortality from pandemic A/H1N1 2009 influenza in England: public health surveillance study , 2009, BMJ : British Medical Journal.

[9]  Libo Dong,et al.  Cross-reactive antibody responses to the 2009 pandemic H1N1 influenza virus. , 2009, The New England journal of medicine.

[10]  Robert Schechter,et al.  Factors associated with death or hospitalization due to pandemic 2009 influenza A(H1N1) infection in California. , 2009, JAMA.

[11]  A. Puren,et al.  Interim report on pandemic H1N1 influenza virus infections in South Africa, April to October 2009: epidemiology and factors associated with fatal cases. , 2009, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[12]  A. Gilsdorf,et al.  Influenza A(H1N1)v in Germany: the first 10,000 cases. , 2009, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[13]  P. Barboza,et al.  Epidemiology of fatal cases associated with pandemic H1N1 influenza 2009. , 2009, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[14]  M. Biggerstaff,et al.  H1N1 2009 influenza virus infection during pregnancy in the USA , 2009, The Lancet.

[15]  E. Lyons,et al.  Pandemic Potential of a Strain of Influenza A (H1N1): Early Findings , 2009, Science.

[16]  R. Mikolajczyk,et al.  Social Contacts and Mixing Patterns Relevant to the Spread of Infectious Diseases , 2008, PLoS medicine.

[17]  J. Benzler,et al.  SurvNet Electronic Surveillance System for Infectious Disease Outbreaks, Germany , 2007, Emerging infectious diseases.

[18]  J. Stockman.  H1N1 2009 influenza virus infection during pregnancy in the USA , 2011 .