Safety and immunogenicity of a DTaP-IPVVero (serum-free) combination vaccine in comparison to DTaP-IPVMkc when administered simultaneously with Haemophilus influenzae type b conjugate vaccine (PRP-T) in children at 2, 3.5, 5 and 16 months of age

In a phase III, double blind, randomized, noninferiority, multi-centre clinical trial, 817 infants were included and randomly assigned to vaccination with DTaP-IPVVero (N = 410) or DTaP-IPVMkc (N = 407) vaccines (Statens Serum Institut (SSI), Denmark) in the right thigh. All infants were vaccinated with Act-HIB® (Sanofi Pasteur, France) in the left thigh at the same time. The vaccination schedule was 2, 3.5, 5 and 16 months and serum samples were obtained at 6, 16 and 17 months. The primary objective was to demonstrate noninferiority of DTaP-IPVVero to DTaP-IPVMkc as regards immunological protection against polio virus types 1, 2 and 3. Furthermore, the immunogenicity of all vaccine antigens and the safety profile of the vaccines were assessed. The study demonstrated that DTaP-IPVVero was noninferior to DTaP-IPVMkc. All antibody concentrations/titres remained at an acceptable level from the end of the primary vaccination series (i.e. 2, 3.5 and 5 months) until the time of the booster vaccination at 16 months. A good booster response was, furthermore, demonstrated for all antigens. No vaccine-related serious adverse events and no injection site granulomas or swelling of the entire thigh occurred. The frequencies of local injection site erythema and swelling as well as systemic adverse events such as fever, irritability, somnolence and decreased appetite were low and acceptable in both treatment groups. In conclusion, DTaP-IPVVero is immunogenic and safe for primary vaccination and for booster vaccination of healthy children.