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 ⩽0.15 µg/mL in children who had received 4 doses of vaccine: from 8.65 µg/mL (prevalence, 99.4%) after 0–2 months to 0.8 µg/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... Mehr ...