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Background: It has not yet been demonstrated whether 2 doses of inactivated quadrivalent influenza vaccine (IIV4) prime a booster response in infants. We evaluated the anamnestic immune response to an IIV4 in children 17-48 months of age., Methods: Children were randomized to 2 doses of IIV4 or control in the primary phase III study (NCT01439360). One year later, in an open-label revaccination extension study (NCT01702454), a subset of children who received IIV4 in the primary study (primed group) received 1 IIV4 dose and children who received control in the primary study (unprimed) received 2 IIV4 doses 28 days apart. The primary objective was to evaluate hemagglutination inhibition (HI) antibody titers 7 days after first IIV4 vaccination in the per-protocol cohort (N = 224 primed; N = 209 unprimed). Neutralizing and antineuraminidase antibodies were also measured. Safety was analyzed in the total vaccinated cohort (N = 241 primed; N = 229 unprimed)., Results: An anamnestic response was observed in primed children relative to unprimed controls, measured by age-adjusted geometric mean HI titer ratios against strains homologous (A/H1N1: 9.0; B/Victoria: 3.9) and heterologous (A/H3N2: 2.7; B/Yamagata: 6.7) to those in the primary vaccination series. The anamnestic response in primed children included increases in neutralizing antibodies (mean geometric increase: 5.0-10.6) and antineuraminidase antibodies (4.9-8.8). No serious adverse events related to vaccination were reported., Conclusions: In this study, 2-dose priming with IIV4 induced immune memory that was recalled with 1-dose IIV4 the following year to boost HI, antineuraminidase and neutralizing antibodies, even though the IIV4 strain composition partially changed.

Background: Booster vaccination with the combined Haemophilus influenza type b-Neisseria meningitides serogroup C-tetanus toxoid vaccine (Hib-MenC-TT) has been reported to induce different MenC antibody responses depending on the priming vaccines, with a possible impact on long-term protection. Here, the five-year persistence of immune responses induced by a booster dose of Hib-MenC-TT was evaluated in toddlers primed with either Hib-MenC-TT or MenC-TT., Methods: This is the follow-up of a phase III, open, randomized study, in which a Hib-MenC-TT booster dose was given at 13.14 months of age to toddlers primed with either 3 doses of Hib-MenC-TT or 2 doses of MenC-TT in infancy. Children in the control group had received 3 primary doses and a booster dose of MenC-CRM197. Functional antibodies against MenC were measured by a serum bactericidal assay with rabbit complement (rSBA-MenC) and antibodies against Hib polyribosylribitol phosphate by enzyme-linked immunosorbent assay. Serious adverse events considered by the investigator to be possibly related to vaccination were to be reported throughout the study., Results: At 66 months postbooster, rSBA-MenC titers ≥8 were retained by 82.6% of children primed with Hib-MenC-TT, 94.1% of children primed with MenC-TT, and 60.9% of children in the control group. All children who received the Hib-MenC-TT booster dose retained anti- polyribosylribitol phosphate concentrations ≥0.15 μg/mL. No serious adverse events considered possibly related to vaccination were reported., Conclusions: There is evidence of good antibody persistence against MenC and Hib for more than five years postbooster vaccination with Hib-MenC TT in toddlers primed with Hib-MenC-TT or MenC-TT.

Background: A combined Haemophilus influenzae type b and Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine (Hib-MenC-TT) may be a convenient alternative to separate Hib and MenC conjugate vaccines., Methods: Healthy infants randomized in a previous study for priming at 2, 4, and 6 months: Hib-MenC-TT primed group, 3 doses of Hib-MenC-TT + DTPa-HBV-IPV (N = 87); MenC-TT primed group, 2 doses of MenC-TT (NeisVac-C; Baxter Healthcare SA, Zuürich, Switzerland) + 3 doses of DTPa/Hib containing vaccines (N = 178); MenC-CRM primed group, 3 doses of MenC-CRM197(Meningitec; Wyeth Corporation Delaware, Madison, NJ) + DTPa-HBV-IPV/Hib (N = 93). At 13-14 months of age, Hib-MenC-TT and MenC-TT primed groups received a Hib-MenC-TT booster dose and the MenC-CRM primed group a booster dose of DTPa-HBV-IPV/Hib. Blood samples were taken before and at 1 and 18 months postbooster., Results: Before the booster dose, persistence of anti-polyribosyl ribitol phosphate (PRP) antibody concentration > or =0.15 microg/mL in the Hib-MenC-TT (96.4%) and MenC-TT (96.1%) primed groups and of MenC bactericidal titers > or =1:8 in the Hib-MenC-TT primed group (96.3%) was statistically significantly higher than in the MenC-CRM primed group (86.4% and 85.4%, respectively). One month after the Hib-MenC-TT booster, 99.2% subjects in the Hib-MenC-TT primed + MenC-TT primed pooled groups had anti-PRP levels > or =1 microg/mL, and 99.6% had SBA-MenC titers > or =1:128. The Hib-MenC-TT booster tended to be less reactogenic than the DTPa-HBV-IPV/Hib control and no serious adverse events related to vaccination were reported. Eighteen months after boosting with Hib-MenC-TT, SBA-MenC titers > or =1:8 persisted in 92.7% subjects and anti-PRP > or =0.15 microg/mL persisted in 99.4%., Conclusions: Primary immunization with 3 doses of Hib-MenC-TT coadministered with DTPa-HBV-IPV induced antibodies that persisted up to the second year of life. The Hib-MenC-TT booster administered to primed toddlers induced robust and persistent antibody responses to both the Hib and MenC components and had an acceptable safety profile.

Background: This phase II study evaluated the immunogenicity and reactogenicity of primary vaccination with a novel Hib-MenC conjugate vaccine (GlaxoSmithKline [GSK] Biologicals) coadministered with DTPa-HBV-IPV (GSK Biologicals) at 2, 4 and 6 months., Methods: Healthy infants were randomized to receive Hib-MenC coadministered with DTPa-HBV-IPV (N = 117) or MenC-CRM (Wyeth) coadministered with DTPa-HBV-IPV/Hib (GSK Biologicals; N = 120) at 2, 4 and 6 months. Antibody concentrations were measured before vaccination and after doses 2 and 3. Solicited local and general symptoms, unsolicited symptoms and serious adverse events (SAEs) were recorded., Results: All subjects in the Hib-MenC group had seroprotective titers of anti-PRP antibodies (>or=0.15 microg/mL) and SBA-MenC titers (>or=1:8) 1 month after the third dose. These responses were noninferior to those seen in the control group, in which a 99.1% seroprotection rate was observed for both Hib and MenC. At that time, anti-PRP and SBA-MenC GMTs were significantly higher in the Hib-MenC group (12.8 microg/mL and 2467.1 microg/mL, respectively) than in the control group (3.8 microg/mL and 1833.7 microg/mL). High seroprotection rates were already observed after the second dose of Hib-MenC; 96.4% and 100% of subjects were seroprotected to Hib and MenC, respectively. Immune responses to coadministered antigens were unimpaired; seroprotection/vaccine response rates >or=96.5% were recorded postdose 3 in the Hib-MenC group. No differences in reactogenicity were seen between the 2 study groups., Conclusions: Coadministration of a Hib-MenC conjugate vaccine with DTPa-HBV-IPV is well tolerated and immunogenic, and does not impair the immune response to any of the coadministered antigens.

Children 17-20 months of age (N = 344) received a diphtheria-tetanus toxoids-acellular pertussis (DTPa)-inactivated poliovirus vaccine (IPV)/Haemophilus influenzae (Hib) booster after a 3-dose primary vaccination course with DTPa-hepatitis B vaccine-IPV/Hib plus conjugate meningococcal C vaccine-CRM. Seroprotection rates were >80% (diphtheria, tetanus, hepatitis B, polio and polyribosylribitol phosphate) before and > or =96.6% (diphtheria, tetanus, polio and polyribosylribitol phosphate) after booster vaccination. The booster was well-tolerated (fever >39.5 degrees C after <2% of doses; large swelling reactions after 6.3% of doses).

Aim: To evaluate the immunogenicity and safety of 3 doses of the combined diphtheria-tetanus toxoids-acellular pertussis-hepatitis B virus-inactivated poliovirus/Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) vaccine (Infanrix hexa) when coadministered with a CRM197-conjugated meningococcal C vaccine (Meningitec) at different injection sites during the same visit or during separate visits., Methods: Healthy infants were randomized in an open randomized multicenter study to receive either the DTPa-HBV-IPV/Hib and meningococcal C conjugate vaccines during the same vaccination visit at 2, 4 and 6 months of age (coadministration group) or the DTPa-HBV-IPV/Hib vaccine at 2, 4 and 6 months of age and the meningococcal C conjugate vaccine at 3, 5 and 7 months of age (separate administration group)., Results: The immunogenicity analysis included 452 infants, 228 in the coadministration group and 224 in the separate administration group. One month after primary vaccination, 99.1% of subjects in both groups achieved anti-polyribosylribitol phosphate antibody concentrations >/=0.15 microg/mL. The vaccine response against pertussis antigens was at least 99.1% in both groups. For all other DTPa-HBV-IPV/Hib vaccine antigens, at least 97.8% of all subjects of both groups were seroprotected. In addition, 99.5% of all subjects had meningococcal C bactericidal antibody titers >/=1/8 and 99.1% >/=1/128. Coadministration of both vaccines did not result in an increased local or general reactogenicity compared with separate administration., Conclusion: Coadministration of the combined DTPa-HBV-IPV/Hib vaccine and the meningococcal C conjugate vaccine during the same vaccination visit was immunogenic and safe.