Hepatitis B and pertussis antibodies in 4- to 5-year-old children previously vaccinated with different hexavalent vaccines

In randomized active-comparator controlled studies, DTaP5-HB-IPV-Hib showed comparable immunogenicity and safety to other licensed vaccines. This study assessed persistence of anti-hepatitis B surface antigen (HBs) and anti-pertussis antibodies, when children were 4 to 5 years of age, 3 to 4 years after initial infant/toddler hexavalent vaccination. This was an extension of 2 European studies in which infants/toddlers received either DTaP5-HB-IPV-Hib or DTaP3-HB-IPV/Hib on a 2 + 1 or 3 + 1 schedule. Primary endpoints included percentages with anti-HBs ≥10 mIU/mL, and anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA), anti-pertactin (PRN), and anti-fimbriae types 2 & 3 (FIM) greater than or equal to the lower limit of quantitation (LLOQ). One month after 2 + 1 or 3 + 1 dosing, nearly all toddlers had anti-HBs ≥10 mIU/mL, and responded to the received pertussis antigens. Approximately 3 to 4 years later, 65.8%-70.2% in the DTaP5-HB-IPV-Hib and 82.0%-83.7% in the DTaP3-HB-IPV/Hib groups, respectively, had anti-HBs ≥10 mIU/mL. Percentages of children with pertussis antibodies above LLOQ after 2 + 1 dosing were 58.4% and 41.5% (anti-PT), 80.9% and 88.3% (anti-FHA), 66.1% and 72.6% (anti-PRN), and 94.4% and 3.3% (anti-FIM), in the DTaP5-HB-IPV-Hib and DTaP3-HB-IPV/Hib groups, respectively. This study demonstrated, as expected, waning of hepatitis B and pertussis antibodies during the 3 to 4 years after completion of a 3 + 1 or 2 + 1 hexavalent vaccination schedule. Nonetheless, anti-HBs levels ≥10 IU/mL and detectable antibodies against acellular pertussis antigens persisted in most study participants. The implications of these findings for the long-term prevention of hepatitis B and pertussis are further discussed.