RÉSUMÉ
The safety and immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV, Synflorix™) were assessed in 240 healthy Chilean children randomized to receive 3 doses of PHiD-CV (PHiD-CV group) or hepatitis A vaccine (HAV control group) at 2-4-6 months of age. All were offered 1 HAV dose at 12 months (outside study). The PHiD-CV group received a second HAV dose at 18-21 months and PHiD-CV booster at 20-23 months. The HAV control group received 2 PHiD-CV catch-up doses at 18-21 and 20-23 months. Adverse events were recorded and pneumococcal antibody responses and opsonophagocytic activity (OPA) were measured. Both PHiD-CV vaccination schedules were well tolerated and immunogenic against the pneumococcal vaccine serotypes and protein D. The reactogenicity of PHiD-CV primary, booster and catch-up doses was in line with previous PHiD-CV studies, although generally higher than with HAV. For each vaccine serotype, the percentage of subjects with antibody concentrations ≥0.2 µg/ml (GSK's 22F-inhibition ELISA) was at least 93.2% following 3 PHiD-CV primary doses and at least 97.4% post-booster; percentages with OPA titers ≥8 were at least 91.7% post-booster. After 2-dose catch-up, at least 94.3% of children had antibody concentrations ≥0.2 µg/ml against each serotype except 6B (84.3%); at least 95.2% had OPA titers ≥8 except against serotypes 1, 5 and 6B. In conclusion, the safety profiles of 2 PHiD-CV vaccination schedules (3-dose primary plus booster and 2-dose catch-up) were in line with previous studies and PHiD-CV was immunogenic for all 10 vaccine serotypes and protein D.