To evaluate safety and immunogenicity of the pneumococcal 7-valent conjugate vaccine (PCV7) when administered to infants with sickle cell disease (SCD) at 2, 3, and 4 months of age with a booster dose of a 23-valent pneumococcal polysaccharide vaccine (PS-23) at 15 to 18 months of age.
This open-label multicenter study in France enrolled 2-month-old infants with SCD. Blood samples for the determination of antibody concentrations to vaccine serotypes were obtained immediately before and 1 month after the primary immunization, and before and 1 month after the PS-23 booster. Local and systemic reactions were recorded on diary cards.
Of the 51 infants enrolled, 49 received primary immunization and 46 received the booster dose. After primary immunization ≥95% of the subjects had antibody titers ≥0.35 μg/mL for the 7 serotypes. After boosting, geometric mean concentrations were high for all serotypes, ranging from 6.32 μg/mL (serotype 18C) to 29.49 μg/mL (serotype 4). Except for 1 case after administration of the booster dose, all fevers reported were less than 39°C. No vaccine-related serious adverse events were reported.
PCV7 administered at 2, 3, and 4 months of age in infants with SCD was well-tolerated, highly immunogenic, and primed for immune memory as indicated by the dramatic response to the PS-23 dose administered at 15–18 months in this study. However, the current recommended schedule is to boost with the PCV7 at 12–15 months of age and for these high-risk children, to enlarge the protection with a subsequent PS-23 dose at 2 years of age.
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From the *CHI Créteil, France; †Inserm U763 and AP-HP Hôpital Robert Debré, Paris, France; ‡Hôpital Necker, Paris, France; and §Wyeth, Paris, France.
Accepted for publication June 21, 2007.
This study was sponsored by Wyeth Pharmaceuticals.
Address for correspondence: Philippe Reinert, Service de Pédiatrie, Centre Hospitalier Intercommunal de Créteil, 40, avenue de Verdun 94010, Creteil, France. E-mail: firstname.lastname@example.org or Philippe.email@example.com.