Vaccine responsiveness in premature infants

An Immunological Perspective on Neonatal Sepsis

“…Knowledge of the maturation in activity of PRRs across stages of development is also important because of the adjuvant role activation of these receptors play during immunizations. Accordingly, premature infants do tend to display significantly reduced antibody responses to routine vaccines [18], a pattern that is also mirrored in the elderly [19]. Further, the complement system is also functionally impaired in neonates born prematurely, as evidenced in a decrease in complement proteins C3a, factor H, factor I [20], also limiting pathogen recognition and clearance.…”

Vaccination of Preterm Infants

“…And this is the main problem for preterm infants: low frequency of diseases associated with low numbers of infants that would be required for such clinical trials. A systematic review was published recently determining vaccine responsiveness to tetanus, diphtheria, meningococcal C and pneumococcal conjugates, Haemophilus influenzae type B, polio and pertussis [6]. The focus of this review was to determine vaccine immunogenicity using immunological correlates of protection and to estimate whether an individual preterm infant was immune based on a "putative protective antibody level".…”

Vaccinating premature infants in a Special Care Baby Unit in the UK: results of a prospective, non-inferiority based, pragmatic case series study

“…For the latter, antibody responses are generally weaker in the first year of life than in older aged children and adults. 1,2 Vaccine trial data have demonstrated that using a schedule of multiple doses with adjuvants and conjugated preparations (for TI-2 antigens) is generally effective in protecting premature infants. 1,2 Vaccine efficacy studies are, however, conducted in a defined clinical population using protocols that require strict adherence to the schedules and (usually) a limited number of vaccine preparations.…”

“…1,2 Whilst vaccination is clearly one mechanism for overcoming these defects in premature infants, impaired functioning of both innate and adaptive systems, means that for particular vaccine immunogens, a suboptimal immunological response may still result. Thus research suggests that dendritic cell/monocyte function in some and possibly all premature infants is less effective at recognizing and processing immunogens than full term infants, which in turn is less effective than in older infants.…”

“…A limited T-cell repertoire and defects in B cell activity further impact on this impaired functioning. 1,2 Vaccinating premature infants in a special care baby unit in the UK…”