The immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was assessed and compared with the 7-valent pneumococcal conjugate vaccine (7vCRM).Methods:
Healthy subjects (1650) were randomized to be vaccinated with 3 doses of PHiD-CV or 7vCRM (Prevenar™/Prevnar™) at 2-3-4 months of age and a fourth booster dose at 12–18 months. Serotype-specific pneumococcal responses (GlaxoSmithKline's ELISA with 22F-inhibition) and opsonophagocytic activity (OPA) were measured 1 month after primary and booster vaccinations.Results:
The primary objective to demonstrate noninferiority of PHiD-CV versus 7vCRM (in terms of percentage of subjects with antibody concentration ≥0.2 μg/mL) for at least 7 of the 10 vaccine serotypes was reached as noninferiority was demonstrated for 8 serotypes. Although, noninferiority could not be demonstrated for ELISA responses against serotypes 6B and 23F, a post-hoc analysis of the percentage of subjects with OPA titers ≥8 suggested noninferiority for the 7 serotypes common to both vaccines including 6B and 23F.Results:
Priming of the immune system against all vaccine serotypes was confirmed by robust increases in ELISA antibody levels (∼6.0–17 fold) and OPA titers (∼8–93 fold) after a fourth consecutive dose of PHiD-CV.Conclusions:
PHiD-CV induces ELISA and functional OPA antibodies for all vaccine serotypes after primary vaccination and is noninferior to 7vCRM in terms of ELISA and/or OPA threshold responses. Effective priming is further indicated by robust booster responses.