Invasive pneumococcal disease in children prior to implementation of the conjugate vaccine in the Zurich region, Switzerland
Objective: To describe symptoms, disease manifestations and outcome of invasive pneumococcal disease in children prior to implementation of the 7-valent conjugate vaccine. Patients and methods: Analysis of children younger than 16 years of age with invasive pneumococcal disease (IPD; n=119) hospitalized in the University children's hospital Zürich during a period of 5.5 years. IPD was defined as disease with isolation of Streptococcus pneumoniae from a normally sterile body site. 90 children with culture-confirmed IPD without underlying illness at risk for invasive disease were included. Symptoms on admission, disease manifestations and rate of complications were analyzed as part of a quality control of treatment. Results: IPD in 90 children (age: median 2, mean 3.2 years) included 15 with meningitis, 16 with septicaemia, 14 with bacteraemia, 24 with pneumonia and 21 with skin, bone and joint infections. Symptoms of IPD most often described were fever, and gastrointestinal symptoms (abdominal pain, vomiting, or diarrhoea) and coughing. More than 90% of children with pneumonia were coughing. Most importantly, clinical signs significantly predictive for severe IPD included tachycardia for sepsis, tachypnoea for pneumonia, and meningeal signs for meningitis. Leukocyte, neutrophil and platelet counts were lower and C-reactive protein concentration were higher on admission in children with complicated than in children with uncomplicated IPD but due to wide overlap of these numbers the difference between was not of prognostic help to predict clinical course and outcome. Overall, 40% of children with IPD manifested complications and IPD showed a mortality rate of 6.6%. Conclusions: IPD is a serious disease with a high complication rate and mortality. The clinical sings tachycardia, tachypnoea and meningism were highly predictive for severe IPD. The initial clinical presentation and laboratory evaluation were mostly unpredictable with respect to complications and outcome in contrast to the clinical signs.