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

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).