Pneumococcal vaccinations effectively prevent blood culture-negative infections that resemble occult pneumococcal bacteraemia or bacteraemic pneumococcal pneumonia at one to 36 months of age.
OBJECTIVE
The occurrence of blood culture-positive pneumococcal bacteraemia and bacteraemic pneumonia decreased after large-scale pneumococcal vaccinations were introduced. The aim of this study was to evaluate the effect of pneumococcal vaccinations on hospitalisations due to blood culture-negative infections with fever and leucocytosis, without any other focus than pneumonic infiltration.


METHODS
This was a retrospective hospital chart review covering the prevaccination era of 2008-2009 and postvaccination era of 2012-2013. The number of study subjects with fever and blood leucocytosis of >17.5 × 10E9/L at one to 36 months of age was 202.


RESULTS
The incidence of hospitalisation for infections associated with fever and leucocytosis, when pneumonic infiltration was present on the chest radiograph, was 4.7/10 000/year, with a 95% confidence interval (95% CI) of 2.2-8.8 in children under 36 months in 2012-2013. When pneumonic infiltration was not present, the respective incidence was 14.6/10 000/year (95% CI: 9.6-21.1). The figure from the 2008-2009 prevaccination era was 11.3 (95% CI: 8.1-15.3) when pneumonic infiltration was present and 24.0/10 000/year (95% CI: 19.2-29.7) when pneumonic infiltration was absent.


CONCLUSIONS
This study provides evidence of the effectiveness of pneumococcal vaccinations in preventing blood culture-negative infections that resembled occult pneumococcal bacteraemia (pneumococcaemia) or bacteraemic pneumococcal pneumonia at one to 36 months of age.
Centre for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
Neea
N
Laaksonen
Centre for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
Lilja
L
Rintamäki
Centre for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
Matti
M
Korppi
D016470:Bacteremia / Q000175:diagnosis / Q000382:microbiology / Q000517:prevention & control*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010400:Penicillin G / Q000627:therapeutic use; D022242:Pneumococcal Vaccines; D011018:Pneumonia, Pneumococcal / Q000175:diagnosis / Q000188:drug therapy / Q000517:prevention & control*; D012189:Retrospective Studies
D022242:Pneumococcal Vaccines; D010400:Penicillin G
Incidence; Leucocytes; Nonfocal infection; Pneumococcal vaccination; Pneumonic infiltration; Toddler