Immunogenicity, reactogenicity and safety of three-dose primary and booster vaccination with combined diphtheria-tetanus-whole-cell pertussis-hepatitis B-reduced antigen content Haemophilus influenzae type b vaccine in Filipino children.

OBJECTIVES: To evaluate the immunogenicity, reactogenicity and safety of primary and booster vaccination with DTPw-HBVLT/Hib2.5 vaccine containing low thiomersal and reduced quantities of Hib polysaccharide (PRP). BACKGROUND: Combined DTP vaccines have high global coverage. Thus, the addition of new antigens to existing DTP vaccines is the most effective way to ensure high coverage. METHODS: 192 healthy infants were randomized to receive the investigational DTPw-HBVLT/Hib2.5 vaccine or licensed DTPw-HBV/Hib10 at 6, 10, 14 weeks. Immune memory to the Hib antigen was assessed through administration of plain PRP challenge at 10 months in 50% of subjects. Challenged and unchallenged subjects respectively received a DTP-HBV or DTPa-HBV/Hib booster at 15-18 months of age. Antibody responses were measured using enzyme-linked immunosorbent assay (ELISA) and reactogenicity was assessed using diary cards. RESULTS: One month post-primary vaccination, 100% and ≥ 93.7% of subjects in both groups had anti-PRP antibody concentrations ≥ 0.15 µg/mL and ≥ 1.0 µg/mL, respectively. Robust responses to PRP were observed after the 10 month plain PRP challenge and booster responses were observed in unchallenged subjects after the booster dose at 15-18 months of age. Post-primary and post-booster responses to the other vaccine antigens were at least as high in the DTPw-HBVLT/Hib2.5 group versus the DTPw-HBV/Hib10 group. The reactogenicity profile of the DTPw-HBVLT/Hib2.5 vaccine was acceptable. CONCLUSION: The DTPw-HBVLT/Hib2.5 combination vaccine with reduced thiomersal and Hib content had equivalent immunogenicity and tolerability versus the full standard DTPw-HBV/Hib10 vaccine. DTPw-HBVLT/Hib2.5 or DTPw-HBV/Hib10 vaccines can contribute to reducing childhood diseases through ensuring high vaccine coverage in mass vaccination programs. ClinicalTrials.gov identifiers: NCT 01061541, NCT00158808.

Repeated administration of a reduced-antigen-content diphtheria-tetanus-acellular pertussis and poliomyelitis vaccine (dTpa-IPV; Boostrix™ IPV).

BACKGROUND: The rising incidence of pertussis amongst adults and adolescents in industrialized countries could be reduced by replacing tetanus and diphtheria (Td) boosters with reduced-antigen-content dT-acellular pertussis (dTpa)vaccines. Repeated administration of a dTpa-IPV (dTpa-inactivated poliomyelitis; BoostrixTM Polio, GlaxoSmithKline)booster to adolescents, 5 years after their previous dose was evaluated. RESULTS: Before the second dTpa-IPV booster, the percentage of subjects who were seroprotected/seropositive was: 98.2% (D); 98.5% (T); 40.6% (PT); 99.7% (FHA); 97.0% (PRN); 98.8% (anti-polio 1); 99.7% (anti-polio 2); 97.0% (anti-polio 3). One month after the second dTpa-IPV dose, all subjects were seroprotected against D, T and polio and anti-pertussis booster responses (seroconversion or ≥2-fold increase) were seen in 93.3% (PT), 93.4% (FHA) and 95.2% (PRN) of subjects.During 4-day follow-up, 4.1% subjects recorded grade 3 pain; 4.6% and 3.6% recorded redness or swelling >50 mm, respectively. No serious adverse events were recorded. The incidence of symptoms was not higher than after the previous booster. METHODS: 415 subjects (mean age 11.4 years) who had received either dTpa-IPV or dTpa + IPV at age 4­8 years, all received one dose of dTpa-IPV in this open, phase IV trial. Blood samples were taken before and one-month post-vaccination. Antibody concentrations against D, T, pertussis toxoid (PT), filamentous haemagglutinin (FHA), pertactin (PRN) and polio antigens were determined. Reactogenicity and safety was assessed. CONCLUSIONS: A second dTpa-IPV booster was highly immunogenic and well tolerated in this population of adolescents, supporting the repeated administration of BoostrixTM Polio. This study is registered at www.clinicaltrials.gov NCT00635128.