Inoue M, et al. - Researchers tested the safety as well as immunogenicity of an investigational C difficile vaccine comprising a mixture of genetically detoxified and chemically inactivated toxoids, A and B, among healthy Japanese adults aged 65 to 85 years. In this randomized, observer-blinded, placebo-controlled phase 1 study, participants were administered 100 or 200 μg of C difficile vaccine or placebo in a 3:3:2 ratio, respectively, at 0, 1, and 6 months (month regimen) or 1, 8, and 30 days (day regimen). In the month regimen, local reactions seen in up to 33.3% of patients per dose, with largely greater percentages seen in the 200-μg group. According to the findings, administration of the C difficile vaccine to healthy older Japanese adults at 0, 1, and 6 months was found safe, well tolerated, and immunogenic. The continued development of this vaccine was supported.