Invasive pneumococcal disease (IPD) in children may manifest as bacteremia/sepsis, bacteremic pneumonia, or meningitis, with serious outcomes that include hospitalization, neurologic sequelae, or death. The risk of severe or fatal outcome of disease is associated with host-related factors, such as age or comorbid conditions. Furthermore, there is an ongoing discussion about organism-related factors, such as the pneumococcal serotype.
Data on 494 children aged <16 years hospitalized for IPD between 1997 and 2003 in pediatric hospitals in Germany were analyzed. Serotype specific case-fatality rates and rates of severe outcome were compared using standardized mortality ratios (SMR). The risk of severe or fatal outcome for the serotype with the highest case-fatality rate was further analyzed using multivariate logistic regression adjusting for age younger than 1 year, meningitis, sex, and immunocompromised status as potential confounders.
The overall case-fatality rate was 5.3% and the rate of severe outcome was 17.0%. Serotype 7F had the highest case-fatality rate (14.8%, SMR 3.1), followed by serotypes 23F (8.3%, SMR 1.7) and 3 (8.3%, SMR 1.7). The highest rate of severe outcome was also observed for 7F (40.7%, SMR 2.4). Multivariate analysis showed an odds ratio of 4.3 (1.3–14.7) for fatal outcome and 4.0 (1.6–10.4) for severe outcome comparing 7F to all other serotypes.
In this study population, serotype 7F accounted for a higher risk of severe and fatal outcome than other serotypes of Streptococcus pneumoniae. In describing the epidemiology of IPD, the serotype-specific risk for severe or fatal outcome is an important complement to other serotype-specific aspects like incidence and antibiotic resistance pattern.
From the *Division of Epidemiology, Institute of Social Pediatrics and Adolescent Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany; †Robert Koch Institute, Berlin, Germany; and ‡Institute of Medical Microbiology and National Reference Centre for Streptococci, University Hospital RWTH Aachen, Aachen, Germany.
Accepted for publication July 24, 2008.
Supported in part by grant RKI-415/1369235 from the German Ministry of Health (to B.F.G.), and by a grant from Wyeth, Germany.
Address for correspondence: Simon Rückinger, MSc, Division of Epidemiology, Ludwig-Maximilians-University of Munich, Institute of Social Pediatrics and Adolescent Medicine, Heiglhofstr 63, 81377 München, Germany. E-mail: firstname.lastname@example.org.