Invasive disease caused by Haemophilus influenzae in Sweden 1997–2009; evidence of increasing incidence and clinical burden of non-type b strains  F. Resman, M. Ristovski, J. Ahl, A. Forsgren, J.R. Gilsdorf, A. Jasir, B. Kaijser, G. Kronvall, K. Riesbeck  Clinical Microbiology and Infection  Volume 17, Issue 11, Pages 1638-1645 (November 2011) DOI: 10.1111/j.1469-0691.2010.03417.x Copyright © 2011 European Society of Clinical Infectious Diseases Terms and Conditions

FIG. 1 The incidence of invasive Haemophilus influenzae disease increased significantly during the years 1997–2009. (a) Total incidence of invasive H. influenzae disease per 100 000 individuals and year from the primary analysis (regardless of serotype) (n = 410). The increase in incidence was statistically significant (p ≤ 0.001). (b) Results from the secondary analysis, comprising 285 defined cases are shown. The increase was statistically significant (p 0.001 and p 0.025 for non-typeable H. influenzae (NTHi) and H. influenzae type f (Hif), respectively). Isolates (n = 17) that had not been saved or previously defined by PCR are indicated as not analysed (N/A). Regardless of the hypothetical outcome of the 17 non-analysed isolates, the increase of invasive NTHi disease remained statistically significant. Clinical Microbiology and Infection 2011 17, 1638-1645DOI: (10.1111/j.1469-0691.2010.03417.x) Copyright © 2011 European Society of Clinical Infectious Diseases Terms and Conditions

FIG. 2 The incidence per patient age group of invasive Haemophilus influenzae disease per 100 000 age-group-sorted individuals at risk is shown. The incidence increased significantly in the age groups 60–80 years and >80 years during the course of the study (p 0.002 and p 0.006, respectively). When the results from PCR serotyping were taken into account, the increase was mainly ascribed to non-typeable H. influenzae (NTHi), but in part also to H. influenzae type f (Hif). Clinical Microbiology and Infection 2011 17, 1638-1645DOI: (10.1111/j.1469-0691.2010.03417.x) Copyright © 2011 European Society of Clinical Infectious Diseases Terms and Conditions

FIG. 3 The clinical burden from invasive Haemophilus influenzae non-type b disease is increasing. The line with filled circles shows total days of hospitalization of patients with invasive H. influenzae non-type b disease per 100 000 individuals at risk in the county of Skåne (left y-axis). The number from 2002 is high because of two cases with unusually long periods of hospitalization (>50 days). The increase in hospitalization days during the years 1997–2009 was significant (p 0.046). For comparison, the black and grey bars show the decreased average times of hospitalization/case due to pneumonia and sepsis in the city of Malmö, Skåne county 2001–2009 (right y-axis). Clinical Microbiology and Infection 2011 17, 1638-1645DOI: (10.1111/j.1469-0691.2010.03417.x) Copyright © 2011 European Society of Clinical Infectious Diseases Terms and Conditions