Decreased Haemophilus colonization in children vaccinated with Haemophilus influenzae type b conjugate vaccine

Synergistic proinflammatory responses induced by polymicrobial colonization of epithelial surfaces

“…Both of these possibilities are especially important in light of increasingly common medical interventions, whereas PdB (100 ng͞ml) has no effect. such as antibiotic therapy or vaccination, that alter the composition of the nasopharyngeal f lora (24,25).…”

Haemophilus influenzae type b conjugate vaccines – A South African perspective

“…This is due to both the opsonic activity of antibodies [50][51][52], as well as complement-mediated bactericidal activity [51,53]. In addition, the vaccine offered indirect protection by delaying nasopharyngeal carriage and asymptomatic colonization amongst vaccinated infants [54][55][56][57]. This provides an additional level of herd immunity [58,59].…”

The continuing role ofHaemophilus influenzaetype b carriage surveillance as a mechanism for early detection of invasive disease activity

“…The presence of Hib nasopharyngeal carriage can indicate disease transmission dynamics. 58 Carriage reduction has been reported successfully in industrialized countries post vaccination, 11,[48][49][50] however, conflicting results on the impact of vaccination on carriage have been obtained from the developing world. And, for some populations, such as rural Alaskan infants, Hib carriage and invasive disease persist despite high uptake of Hib vaccine.…”

“…51 Studies have demonstrated that upon introduction of Hib conjugate vaccine, herd immunity increased and rates of oropharyngeal carriage declined, 50 in some instances studies have failed to detect Hib colonization in those vaccinated or unvaccinated, following the introduction of routine vaccination. 2,16,38,40,52 One study from northern Taiwan detected Hib carriage only in unvaccinated children under five years compared with children vaccinated with at least one dose of HIb conjugate vaccine.…”

“…25 However, despite the marked disappearance of invasive Hib disease, some studies encompassing mostly Indigenous populations report persisting Hib carriage, albeit at lower levels than pre-vaccination carriage. 2,11,21,23,50,53 The issue of persistent Hib carriage in vaccinated populations occurs globally, mostly in minority populations, often despite high levels of vaccine uptake. 2,12 A study of Native Alaskans reported Hib oropharyngeal carriage as high as 9.3% in fully vaccinated under five year old children.…”