A Study To Investigate A Clostridium Difficile Vaccine In Healthy Adults Aged 50 to 85 Years, Who Will Each Receive 3 Doses Of Vaccine.

Proven or suspected prior episode of Clostridium difficile associated diarrhea.

Unstable chronic medical condition or disease requiring significant change in therapy or
hospitalization for worsening disease within 8 weeks before receipt of study vaccine.

Any contraindication to vaccination or vaccine components, including previous anaphylactic
reaction to any vaccine or vaccine-related components.