Antibodies to Haemophilus influenzae serotype b in the Netherlands a few years after the introduction of routine vaccination.
We assessed antibodies to the capsular polysaccharide of Haemophilus influenzae type b (HibPS) in the Dutch population a few years after a mass vaccination against H. influenzae (Hib) was begun. We observed sharp declines in the geometric mean titer (GMT) and the prevalence of HibPS antibodies at levels of < or =0.15 microg/mL in children who had received 4 doses of vaccine: from 8.65 microg/mL (prevalence, 99.4%) after 0-2 months to 0.8 microg/mL (prevalence, 83.3%) after 27-29 months. In adult groups, both the prevalence of HibPS antibodies and the GMT declined significantly with increasing age but remained high (prevalence, > or =83.7%; GMT, 0.73 > or = microg/mL). We conclude that the overall immunity in the Dutch population seems satisfactory. We draw our conclusions from the current serosurveillance study and from the sharp decline in invasive Hib disease noted after the introduction of vaccination. The key questions for the future are (1) whether Hib and cross-reacting organisms will circulate sufficiently to provide natural reexposure, and (2) how long memory immunity will persist after vaccination without reexposure.
van Den Hof
S
S
National Institute of Public Health and the Environment (RIVM), Dept. of Infectious Diseases Epidemiology, Bilthoven, The Netherlands. Susan.van.den.Hof@rivm.nl
de Melker
H E
HE
Berbers
G A
GA
van Der Kraak
P H
PH
Spaendonck
M A
MA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood* / Q000276:immunology; D016667:Bacterial Capsules; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage / Q000276:immunology*; D012703:Serotyping
D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D011135:Polysaccharides, Bacterial