Safety and immunogenicity of the pneumococcal pneumolysin derivative PlyD1 in a single-antigen protein vaccine candidate in adults.

Background: Pneumococcal vaccines based on conserved protein antigens have the potential to offer expanded protection against Streptococcus pneumoniae.

Objective: This study examined the safety and immunogenicity in adults of three doses of a pneumococcal single-antigen protein vaccine candidate formulated with aluminum hydroxide adjuvant and recombinantly derived, highly detoxified, genetically mutated pneumolysin protein (PlyD1).

Methods: This phase I, randomized, placebo-controlled, observer-blinded, dose-escalating study enrolled adults (18-50 years).