Invasive Haemophilus influenzae infections in Germany: impact of non-type b serotypes in the post-vaccine era.
BACKGROUND
Haemophilus influenzae type b (Hib) vaccination led to a significant decrease in invasive bacterial infections in children. The aim of this study was to assess a potential shift to more non-type b invasive infections in a population with high Hib vaccination coverage and to compare the burden of suffering between children with Hib, capsulated non-b and non-capsulated Hi infections.


METHODS
Cases with confirmed invasive Hi infections were ascertained through two independent nationwide active surveillance systems in 1998-2005. Information on possible predisposing conditions and clinical information was available from 2001 onwards.


RESULTS
The total number of reported non-type b Hi cases varied between 10 cases in 1998, 27 in 2000 and 14 in 2005. In each year, non-capsulated serotypes outnumbered capsulated non-type b ones. 192 cases were detected in 2001-2005, more than one half was non-type b and 88% of the non-type b cases were non-capsulated. For cases with Hib/capsulated non-type b infections the most common clinical presentation was meningitis (67% each); 89%/78% had no potential predisposing condition, 75%/72% completely recovered from disease and 6% (each) died. In contrast, meningitis was diagnosed in 34% of the non-capsulated Hi infections, septicaemia in 28% and pneumonia 21%; 62% had no potential predisposing condition, 83% completely recovered and 3% died.


CONCLUSIONS
There was no increase in non-type b Hi invasive infections during 8 years of active surveillance in Germany. Invasive disease due to non-type b Hi is not confined to children with risk factors. In patients with capsulated non-type b Hi infections the proportion of meningitis cases is similar to Hib, but double as high as in non-capsulated Hi.
Kalies
Helen
H
Department Epidemiology, Institute for Social Pediatrics and Adolescent Medicine, Ludwig-Maximilians-University, Munich, Germany. kalies@uni-muenchen.de
Siedler
Anette
A
Gröndahl
Britta
B
Grote
Veit
V
Milde-Busch
Astrid
A
von Kries
Rüdiger
R
D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D005260:Female; D005858:Germany / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D018073:Haemophilus Vaccines / Q000008:administration & dosage; D006193:Haemophilus influenzae / Q000145:classification*; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D008297:Male; D011159:Population Surveillance; D012307:Risk Factors
D018073:Haemophilus Vaccines