Karla Köpke

Estimates of excess medically attended acute respiratory infections in periods of seasonal and pandemic influenza in Germany from 2001/02 to 2010/11.

Background The number of patients seeking health care is a central indicator that may serve several different purposes: (1) as a proxy for the impact on the burden of the primary care system; (2) as a starting point to estimate the number of persons ill with influenza; (3) as the denominator data for the calculation of case fatality rate and the proportion hospitalized (severity indicators); (4) for economic calculations. In addition, reliable estimates of burden of disease and on the health care system are essential to communicate the impact of influenza to health care professionals, public health professionals and to the public. Methodology/Principal Findings Using German syndromic surveillance data, we have developed a novel approach to describe the seasonal variation of medically attended acute respiratory infections (MAARI) and estimate the excess MAARI attributable to influenza. The weekly excess inside a period of influenza circulation is estimated as the difference between the actual MAARI and a MAARI-baseline, which is established using a cyclic regression model for counts. As a result, we estimated the highest ARI burden within the last 10 years for the influenza season 2004/05 with an excess of 7.5 million outpatient visits (CI95% 6.8–8.0). In contrast, the pandemic wave 2009 accounted for one third of this burden with an excess of 2.4 million (CI95% 1.9–2.8). Estimates can be produced for different age groups, different geographic regions in Germany and also in real time during the influenza waves.

Epidemiologischer Steckbrief der pandemischen Influenza (H1N1) 2009 basierend auf Einzelfallmeldungen nach Infektionsschutzgesetz

The aim of the investigation is the descriptive analysis of case-based information from mandatory notifications in the first year of the influenza pandemic (H1N1) 2009 in order to identify and describe epidemiological characteristics and risk factors for severe outcome. Four distinct time periods were defined to describe the age distribution of hospitalized and fatal cases. In contrast, stratified (age, sex) analysis of risk factors was carried out for the whole time period of pandemic influenza activity (notification weeks 18/2009 to 17/2010). Characteristic differences in the age distribution of reported cases were observed according to the time period. Among the reported risk factors, immunosuppression exhibited the highest probability for hospitalization or a fatal outcome (OR=8.82; CI95% 7.3-10.6 and OR=37.4; CI95% 25.5-54.8, respectively). The stratified analysis showed that this was especially pronounced for patients in the age group 60 years and above. Single case-based notifications of pandemic influenza have proven to be an invaluable source of information for assessing the epidemiological characteristics of the influenza pandemic 2009 in Germany. In addition, it allows comparative analysis of certain risk groups for severe disease. The information, thus, provides an important contribution for further developing and improving of public health recommendations.

Epidemiological characteristics of the influenza pandemic (H1N1) 2009 in Germany based on the mandatory notification of cases

The aim of the investigation is the descriptive analysis of case-based information from mandatory notifications in the first year of the influenza pandemic (H1N1) 2009 in order to identify and describe epidemiological characteristics and risk factors for severe outcome. Four distinct time periods were defined to describe the age distribution of hospitalized and fatal cases. In contrast, stratified (age, sex) analysis of risk factors was carried out for the whole time period of pandemic influenza activity (notification weeks 18/2009 to 17/2010). Characteristic differences in the age distribution of reported cases were observed according to the time period. Among the reported risk factors, immunosuppression exhibited the highest probability for hospitalization or a fatal outcome (OR=8.82; CI95% 7.3-10.6 and OR=37.4; CI95% 25.5-54.8, respectively). The stratified analysis showed that this was especially pronounced for patients in the age group 60 years and above. Single case-based notifications of pandemic influenza have proven to be an invaluable source of information for assessing the epidemiological characteristics of the influenza pandemic 2009 in Germany. In addition, it allows comparative analysis of certain risk groups for severe disease. The information, thus, provides an important contribution for further developing and improving of public health recommendations.

Epidemiologischer Steckbrief der pandemischen Influenza (H1N1) 2009 basierend auf Einzelfallmeldungen nach Infektionsschutzgesetz@@@Epidemiological characteristics of the influenza pandemic (H1N1) 2009 in Germany based on the mandatory notification of cases

The aim of the investigation is the descriptive analysis of case-based information from mandatory notifications in the first year of the influenza pandemic (H1N1) 2009 in order to identify and describe epidemiological characteristics and risk factors for severe outcome. Four distinct time periods were defined to describe the age distribution of hospitalized and fatal cases. In contrast, stratified (age, sex) analysis of risk factors was carried out for the whole time period of pandemic influenza activity (notification weeks 18/2009 to 17/2010). Characteristic differences in the age distribution of reported cases were observed according to the time period. Among the reported risk factors, immunosuppression exhibited the highest probability for hospitalization or a fatal outcome (OR=8.82; CI95% 7.3-10.6 and OR=37.4; CI95% 25.5-54.8, respectively). The stratified analysis showed that this was especially pronounced for patients in the age group 60 years and above. Single case-based notifications of pandemic influenza have proven to be an invaluable source of information for assessing the epidemiological characteristics of the influenza pandemic 2009 in Germany. In addition, it allows comparative analysis of certain risk groups for severe disease. The information, thus, provides an important contribution for further developing and improving of public health recommendations.