A gamma-irradiated pneumococcal vaccine elicits superior immunogenicity in comparison to heat or chemically inactivated whole-cell vaccines.

Streptococcus pneumoniae is one of the world's foremost bacterial pathogens, with extensive serotype diversity that impacted the efficacy of current vaccines. Our group have previously reported the generation of a whole cell serotype-independent gamma-irradiated pneumococcal vaccine (Gamma-PN). The present study sought to compare the effect of gamma-irradiation, heat, ethanol, or formalin inactivation on the antigenic structure and immunogenicity of whole-cell pneumococcal vaccines.