The immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was determined following a simplified 2-dose priming and the more commonly employed 3-dose priming both followed by a booster dose.
A total of 351 healthy subjects were primed with PHiD-CV at either 3 and 5 or 3, 4 and 5 months of age followed in all subjects by a booster dose at 11 to 12 months of age. Serotype-specific pneumococcal responses were measured by 22F-inhibition ELISA and opsonophagocytic assays 1 month following primary and booster vaccinations.
Depending on the serotype, the percentages of subjects reaching the ELISA antibody threshold of 0.2 μg/mL were 92.8% to 98.0% following 2 primary doses and 96.1% to 100% following 3 primary doses except for serotype 6B (55.7% and 63.1%, respectively) and serotype 23F (69.3% and 77.6%, respectively). Opsonophagocytic activity (OPA) could be measured in 74.4% to 100% and 88.9% to 100% of the subjects after the 2-dose or 3-dose priming, respectively, except for serotype 1 (60.8% and 62.9%, respectively). In both groups, robust increases in ELISA antibodies and OPA titers were observed for all serotypes after the booster dose. Higher postprimary and postbooster ELISA antibody levels and OPA titers were observed for most serotypes following the 3+1 schedule.
PHiD-CV was immunogenic in both schedules, but further effectiveness data are needed to fully understand the public health benefit to be expected from these schedules in terms of prevention against invasive and mucosal infections.
From the *Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden; †Department of Pediatrics, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark; ‡Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway; §GPP Practice, Dolny Kubin, Slovakia; and ¶Global Clinical Development Center, GlaxoSmithKline Biologicals, Rixensart, Belgium.
Accepted for publication June 24, 2009.
Supported by GlaxoSmithKline Biologicals, Rixensart, Belgium. Dr. SA Silfverdal received consulting fees in the past three years from the commercial entity that sponsored the study. P. Lommel is employed by the commercial entity that sponsored the study. The authors M.R.B., B.H., and H.S. have no conflict of interest to declare. The authors L.S. and D.B. are employed by the commercial entity that sponsored the study and have stock ownership.
Infanrix hexa and Infanrix IPV Hib are trademarks of the GlaxoSmithKline group of companies.
Address for correspondence: Sven Arne Silfverdal, MD, Department of Clinical Sciences, Pediatrics, Umeå University, SE 901 85 Umeå, Sweden. E-mail: firstname.lastname@example.org.
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