Mortality of 2009 pandemic influenza A(H1N1) in Germany

Abstract

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.

High prevalence of asymptomatic carrier state with 2009 pandemic influenza virus in a remote rural South Indian community in the year 2012

“…Further, factors such as diabetes [11], obesity [10] and age [12] which are poor prognostic indicators in symptomatic pandemic H1N1 influenza infection were not associated with asymptomatic carrier state in our study (Table 2). In fact none of the patient characteristics were significantly associated with having asymptomatic carrier state (Table 2).…”

“…Then uni-variate and multi-variate logistic regression analysis was performed using presence of H1N1 infection as the dependent variable and age, gender, BMI, diabetes diagnosis, and HbA1C% as independent variables. Since obesity [10] and diabetes mellitus [11] are known to be poor prognostic factors with symptomatic pandemic influenza infection, we included these variables in the logistic regression model to look for their association with asymptomatic carrier state. Though we planned Cox regression on the 4 weeks follow-up data, we could not perform these as none of the participants who were positive at baseline developed respiratory disease during 4 weeks of follow-up.…”

Risk Factors Associated with Severe Clinical Outcomes of Pandemic H1N1 Infection

“…In Canada it was also shown that 22.6-38% of the critically ill were or had been smokers [11,14]. In California in 2009, 41% of fatal influenza cases had chronic lung disease [10] while in Germany it was reported to be 23.1% [15].…”

“…In Canada it was also shown that 22.6-38% of the critically ill were or had been smokers [11,14]. In California in 2009, 41% of fatal influenza cases had chronic lung disease [10] while in Germany it was reported to be 23.1% [15].Obesity: Obesity has commonly been reported in ICU submissions and patients dying from pdm(H1N1)09 [6,11,12,[15][16][17][18] …”

“…With the exception of 0-1 year old group in general the severity of clinical outcome appeared to be directly proportional to age [5,7,9,10,12,13]. Other key risk factors leading to severe clinical outcomes were asthma, COPD and obesity [10][11][12][13][14][15]although there were a number of severe clinical cases with no known underlying condition [7,[25][26][27][28][29][30][31][32][33]. …”