Persistence of antibodies at 5-6 years of age for children who had received a primary series vaccination with a pentavalent whole-cell pertussis vaccine and a first booster with a pentavalent acellular pertussis vaccine: immunogenicity and tolerance of second booster with a tetravalent acellular vaccine at 5-6 years of age.

Unlabelled: The main objective of this study was to assess in 5-6-year-old French children (n=162) the persistence of antibodies induced by a primary series vaccination (at 2-4 months of age) with a pentavalent whole-cell pertussis combined vaccine (DTwcP-IPV-Hib; Pentacoq) and a first booster (at 12-16 months of age) with a pentavalent two-component acellular pertussis combined vaccine (DTacP-IPV-Hib; Pentavac). The second objective was to evaluate in these 5-6-year-old French children the safety and the immunogenicity of a tetravalent pertussis combined vaccine (DTacP-IPV, Tetravac) given as a second booster.

Results: before the 2nd booster, more than 90% of children had antibody titers above the defined threshold for polyribosyl ribitol phosphate (PRP), tetanus, diphtheria and poliomyelitis; antibody titers were very low for pertussis. One month after the second booster, all children had sero-protective post-booster titers for tetanus, diphtheria and poliomyelitis types 1-3; over 90% of children had a four-fold rise in titers against DTacP-IPV antigens. Adverse events were mostly solicited reactions, with no serious adverse event. A strong anamnestic response was also observed after the second booster injection with Tetravac, with a satisfactory safety profile.

Conclusion: Pentavac and Tetravac (acellular pertussis containing vaccines) may thus be administered as first and second boosters respectively, in children primed with Pentacoq (whole-cell pertussis containing vaccine).