Session Title: VACCINE AND PREVENTION
CELLULAR AND HUMORAL IMMUNE RESPONSES OF PRE-TERM INFANTS TO THE PRIMING WITH PERTUSSIS VACCINES
F. Vermeulen1, V. Verscheure2, E. Damis3, D. Vermeylen4, G. Leloux2, V. Dirix2, C. Locht5, F. Mascart2
1Pediatrics, 2Laboratory of Vaccinology and Mucosal Immunity, Hôpital Erasme - Université Libre de Bruxelles (ULB), 3Pediatric Department, Centre Hospitalier Inter Régional Edith Cavell, 4Neonatal Intensive Care Unit, Hôpital Erasme - Université Libre de Bruxelles (ULB), Bruxelles, Belgium, 5INSERM U629, Institut Pasteur de Lille, Lille, France
Background and aims: As protection against Bordetella pertussis is mediated by both specific antibody and T cell responses, and as it is recommended to vaccinate preterm infants against B. pertussis according to chronological age, we have determined whether highly pre-term infants (≤ 30 weeks) are able to mount these immune responses during vaccine priming.
Methods: 46 premature infants were vaccinated at 2, 3 and 4 months of chronological age with a Tetravalent diphtheria-tetanus-pertussis-polio vaccine mixed with an Haemophilus influenzae Type b vaccine. 22 received an acellular (Pa), and 24 received a whole cell (Pw) pertussis vaccine. Blood samples collected at 2, 3 and 6 months of age were analyzed for specific IgG titers and avidities, as well as for antigen-induced IFN-γ, IL-5 and IL-13 secretions.
Results: In Pa-vaccinated infants, anti-filamentous haemagglutinin and anti-pertusiss toxin IgG were detected in the sera from 6 months-old infants at similar titres and nearly same avidities as age-matched vaccinated full-term infants. Most of the Pa- or Pw-vaccinated infants developed at 3 or 6 months of age an IFN-γ response to the B. pertussis antigens, accompanied by an IL-5 and IL-13 secretion for the Pa-vaccinated infants.
Conclusions: Like full-term infants, most pre-term infants are able to mount at 6 months of age adequate specific humoral and cellular immune responses to the administration of prime pertussis vaccination at chronological age. However, since most severe cases of infection occur before 2 months of age, additional efforts should be made to protect infants already at birth against B. pertussis.