Safety, reactogenicity and immunogenicity of a novel pneumococcal protein-based vaccine in adults: a phase I/II randomized clinical study.

•First safety study of six novel pneumococcal protein-containing vaccine formulations.•Formulations contained dPly alone or dPly and PhtD, alone or with 10 PS-conjugates.•All formulations used as two- or three-dose series in healthy adults were well-tolerated.•All formulations were immunogenic for protein antigens.•PS-conjugate-containing formulations were also immunogenic for the PS-conjugates.