Safety and immunogenicity of a new fully liquid DTPw-HepB-Hib combination vaccine in infants

We assessed the safety and immunogenicity of a fully liquid, DTPw-HepB-Hib combination vaccine (Quinvaxem™) in comparison with separately administered DTPw-Hib and hepatitis B vaccines. Infants participating in this open-label, randomized, phase II study received a primary vaccination course using a 2-3-4 month schedule. Blood samples were taken immediately prior to the first and one month after the third vaccination. Adverse events were assessed over a 7-day post-vaccination period using subject diaries. After completion of the primary vaccination course, 94.7% [95% CI: 89.8-97.7%] of infants receiving the combination vaccine achieved protective anti-HBs antibody titers (≥10 mIU/mL) with a mean 39-fold increase in GMTs in comparison with 99.3% [95% CI: 96.3-100%] seroprotection and a mean 29-fold GMT increase in the comparator group. Diphtheria, tetanus and Haemophilus influenzae type b (Hib) seroprotection rates and pertussis seroconversion rates were also similar between the two groups. There was no statistically significant difference in GMTs for diphtheria between the two groups, but significant differences were shown for tetanus, Hib, and pertussis with higher GMTs for each antigen observed in the comparator group. The combination vaccine was well tolerated, with fever (body temperature ≥38°C) being the most frequently reported adverse event in both the DTPw-HepB-Hib (12.5% [95% CI: 7.7-1 8.8%]) and comparator (12.6% [95% CI: 7.7-19.0%]) groups. This study demonstrated that the fully liquid DTPw-HepB-Hib combination vaccine has safety and immunogenicity profiles similar to the DTPw-Hib and hepatitis B vaccines when administered separately.