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The first wave of pandemic influenza (H1N1) 2009 in Germany: from initiation to acceleration.

Poggensee G, Gilsdorf A, Buda S, Eckmanns T, Claus H, Altmann D, RKI Working Group Pandemic InfluenzaKrause G, Haas W - BMC Infect. Dis. (2010)

Bottom Line: Furthermore, young children (0 to 2 years) (OR = 2.8 [95% CI: 1.5; 5.2]) and persons with influenza-like illness (ILI, OR = 1.4 [95% CI: 1.0; 2.1]) had a higher risk to develop pneumonia compared to other age groups and individuals without ILI.The spread of disease did not result in change of risk groups or severity.Our results show that analyses of case-based information can advise future public health measures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, DGZ-Ring 1, 13086 Berlin, Germany.

ABSTRACT

Background: The first imported case of pandemic influenza (H1N1) 2009 in Germany was confirmed in April 2009. However, the first wave with measurable burden of disease started only in October 2009. The basic epidemiological and clinical characteristics of the pandemic were analysed in order to understand the course of the pandemic in Germany.

Methods: The analysis was based on data from the case-based, mandatory German surveillance system for infectious diseases. Cases notified between 27 April and 11 November 2009 and fulfilling the case definition were included in the study.

Results: Two time periods with distinct epidemiologic characteristics could be determined: 23,789 cases (44.1%) occurred during the initiation period (IP, week 18 to 41), and 30,179 (55.9%) during the acceleration period (AP, week 42 to 45). During IP, coinciding with school summer holidays, 61.1% of cases were travel-related and one death occurred. Strict containment efforts were performed until week 32. During AP the majority of cases (94.3%) was autochthonous, 12 deaths were reported. The main affected age group shifted from 15 to 19 years in IP to 10 to 14 years in AP (median age 19 versus 15 years; p < 0.001). The proportion of cases with underlying medical conditions increased from 4.7% to 6.9% (p < 0.001). Irrespective of the period, these cases were more likely to be hospitalised (OR = 3.6 [95% CI: 3.1; 4.3]) and to develop pneumonia (OR = 8.1 [95% CI: 6.1; 10.7]). Furthermore, young children (0 to 2 years) (OR = 2.8 [95% CI: 1.5; 5.2]) and persons with influenza-like illness (ILI, OR = 1.4 [95% CI: 1.0; 2.1]) had a higher risk to develop pneumonia compared to other age groups and individuals without ILI.

Conclusion: The epidemiological differences we could show between summer and autumn 2009 might have been influenced by the school summer holidays and containment efforts. The spread of disease did not result in change of risk groups or severity. Our results show that analyses of case-based information can advise future public health measures.

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Age distribution of cases with pandemic influenza (H1N1) 2009 infection in Germany from week 24 to week 45 in 2009; age distribution in weeks 24 to 41 (initiation period) and in weeks 42 to 45 (acceleration period).
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Figure 4: Age distribution of cases with pandemic influenza (H1N1) 2009 infection in Germany from week 24 to week 45 in 2009; age distribution in weeks 24 to 41 (initiation period) and in weeks 42 to 45 (acceleration period).

Mentions: Figure 4 shows the age distribution of cases over the weeks. In the initiation period the age group 15 to 24 years constituted 54% of all cases (n = 12,854) dropping to 24.7% (n = 7.441) in the acceleration period. The proportion of school-aged children in the age group 5 to 14 years increased from 16% (n = 3,794) in the initiation period to 43.8% (n = 13,195) in the acceleration period. The median age decreased significantly from 19 years in the initiation period to 15 years in the acceleration period (p < 0.001; table 1).


The first wave of pandemic influenza (H1N1) 2009 in Germany: from initiation to acceleration.

Poggensee G, Gilsdorf A, Buda S, Eckmanns T, Claus H, Altmann D, RKI Working Group Pandemic InfluenzaKrause G, Haas W - BMC Infect. Dis. (2010)

Age distribution of cases with pandemic influenza (H1N1) 2009 infection in Germany from week 24 to week 45 in 2009; age distribution in weeks 24 to 41 (initiation period) and in weeks 42 to 45 (acceleration period).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2902478&req=5

Figure 4: Age distribution of cases with pandemic influenza (H1N1) 2009 infection in Germany from week 24 to week 45 in 2009; age distribution in weeks 24 to 41 (initiation period) and in weeks 42 to 45 (acceleration period).
Mentions: Figure 4 shows the age distribution of cases over the weeks. In the initiation period the age group 15 to 24 years constituted 54% of all cases (n = 12,854) dropping to 24.7% (n = 7.441) in the acceleration period. The proportion of school-aged children in the age group 5 to 14 years increased from 16% (n = 3,794) in the initiation period to 43.8% (n = 13,195) in the acceleration period. The median age decreased significantly from 19 years in the initiation period to 15 years in the acceleration period (p < 0.001; table 1).

Bottom Line: Furthermore, young children (0 to 2 years) (OR = 2.8 [95% CI: 1.5; 5.2]) and persons with influenza-like illness (ILI, OR = 1.4 [95% CI: 1.0; 2.1]) had a higher risk to develop pneumonia compared to other age groups and individuals without ILI.The spread of disease did not result in change of risk groups or severity.Our results show that analyses of case-based information can advise future public health measures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, DGZ-Ring 1, 13086 Berlin, Germany.

ABSTRACT

Background: The first imported case of pandemic influenza (H1N1) 2009 in Germany was confirmed in April 2009. However, the first wave with measurable burden of disease started only in October 2009. The basic epidemiological and clinical characteristics of the pandemic were analysed in order to understand the course of the pandemic in Germany.

Methods: The analysis was based on data from the case-based, mandatory German surveillance system for infectious diseases. Cases notified between 27 April and 11 November 2009 and fulfilling the case definition were included in the study.

Results: Two time periods with distinct epidemiologic characteristics could be determined: 23,789 cases (44.1%) occurred during the initiation period (IP, week 18 to 41), and 30,179 (55.9%) during the acceleration period (AP, week 42 to 45). During IP, coinciding with school summer holidays, 61.1% of cases were travel-related and one death occurred. Strict containment efforts were performed until week 32. During AP the majority of cases (94.3%) was autochthonous, 12 deaths were reported. The main affected age group shifted from 15 to 19 years in IP to 10 to 14 years in AP (median age 19 versus 15 years; p < 0.001). The proportion of cases with underlying medical conditions increased from 4.7% to 6.9% (p < 0.001). Irrespective of the period, these cases were more likely to be hospitalised (OR = 3.6 [95% CI: 3.1; 4.3]) and to develop pneumonia (OR = 8.1 [95% CI: 6.1; 10.7]). Furthermore, young children (0 to 2 years) (OR = 2.8 [95% CI: 1.5; 5.2]) and persons with influenza-like illness (ILI, OR = 1.4 [95% CI: 1.0; 2.1]) had a higher risk to develop pneumonia compared to other age groups and individuals without ILI.

Conclusion: The epidemiological differences we could show between summer and autumn 2009 might have been influenced by the school summer holidays and containment efforts. The spread of disease did not result in change of risk groups or severity. Our results show that analyses of case-based information can advise future public health measures.

Show MeSH
Related in: MedlinePlus