Antibody persistence after primary and booster doses of a pentavalent vaccine against diphtheria, tetanus, acellular pertussis, inactivated poliovirus, haemophilus influenzae type B vaccine among Thai children at 18-19 months of age

Queen Sirikit National Institute of Child Health, Bangkok.
The Southeast Asian journal of tropical medicine and public health (Impact Factor: 0.72). 03/2012; 43(2):442-54.
Source: PubMed


The World Health Organization recommends a booster dose of a pertussis-containing vaccine for children aged 1-6 years, preferably during the second year of life. This study assessed the immunogenicity and safety of a pentavalent combination vaccine containing diphtheria, tetanus, acellular pertussis, inactivated poliovirus, and conjugated-Hib polysaccharide antigens, [(DTaP-IPV//PRP-T (Pentaxim)], as a booster at 18-19 months of age. Participants had received primary doses of the same vaccine at 2, 4 and 6 months of age. Antibody concentrations were measured immediately before and one month after the booster dose. Adverse events were evaluated from parental reports. Geometric mean concentrations (GMCs) or titers (GMTs) decreased from post-primary to pre-booster vaccination; however, at least 94.4% of children had protective levels of anti-tetanus (> or = 0.01 IU/ml), antipoliovirus (> or = 81/dil) and anti-PRP (Hib, > or = 0.15 microg/ml) antibodies prior to the booster. Anti-diphtheria antibody titers > or = 0.01 IU/ml were also observed in the majority of children pre-booster. One month after the booster, seroprotection rates were 99.4% for PRP (> or = 1.0 microg/ml), 95.0% for diphtheria (> or = 0.10 IU/ml) and 100% for tetanus (> or = 0.1 IU/ml) and poliovirus types 1, 2, 3 (> or = 81/dil). At least 93.1% of subjects had 4 fold post-booster increases in anti-pertussis antibody titers. GMCs increased from 14.0 to 307.3 EU/ml and from 13.9 to 271.9 EU/ml for anti-PT and anti-FHA, respectively. Anti-PRP GMC increased from 1.2 to 62.2 microg/ml. The booster was well tolerated. A booster dose during the second year of life was safe and induced a strong immune response, indicative of long-term protection.

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    ABSTRACT: To evaluate an investigational, fully liquid hexavalent diphtheria-tetanus-acellular pertussis-inactivated poliovirus-hepatitis B-Haemophilus influenzae type b (DTaP-IPV-Hep B-PRP-T: Hexaxim™) vaccine for primary and booster vaccination of healthy children in Mexico. Infants (N=1189) were randomized to receive one of three lots of the DTaP-IPV-Hep B-PRP-T vaccine or a licensed hexavalent control vaccine (Infanrix™ hexa) for primary vaccination at 2, 4 and 6 months. All participants who completed the primary series and agreed to participate in the booster part of the study received a dose of the investigational vaccine at 15-18 months of age. Validated serological assays and parental reports were used to assess immunogenicity and safety, respectively. Post-primary vaccination, ≥95.8% of participants in both the DTaP-IPV-Hep B-PRP-T and control groups were seroprotected (SP) against diphtheria, tetanus, poliovirus, hepatitis B and PRP, or had seroconverted (SC) to the pertussis toxin (PT) and filamentous hemagglutinin (FHA) pertussis antigens. The SP/SC rates induced by the three DTaP-IPV-Hep B-PRP-T lots were equivalent. No differences in SP/SC rates were observed between the pooled lots of investigational vaccine and the control vaccine. Antibody persistence at 15-18 months was comparable between groups, with strong increases in all antibody concentrations post-DTaP-IPV-Hep B-PRP-T booster. Both vaccines were well tolerated for primary vaccination, as was the booster dose of DTaP-IPV-Hep B-PRP-T. These study findings confirm the suitability of the combined, fully liquid DTaP-IPV-Hep B-PRP-T vaccine for inclusion in routine childhood vaccination schedules.
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