- Healthy male and female subjects
- Aged 65 to 85 years
Additional Inclusion Criteria for the extension Stage:
- Receipt of all 3 doses of C difficile vaccine (100 µg or 200 µg antigen dose level) in
the original portion of the study.
- Proven or suspected prior episode of Clostridium difficile associated diarrhea
- Unstable chronic medical condition
- Disease requiring significant change in therapy or hospitalization for worsening
disease within 8 weeks before receipt of study vaccine
- Serious chronic disorders
- Congenital or acquired immunodeficiency disorders
- Rheumatologic disorders or other illnesses requiring chronic treatment with known
immunosuppressant medications.
- Active or treated leukemia or lymphoma or bone marrow disorder
- Any contraindication to vaccination or vaccine components including previous
anaphylactic reaction to any vaccine or vaccine-related components
Additional Exclusion Criteria for the Extension Stage:
- Subjects originally randomized to placebo during the original portion of the study.
- Subjects who have already completed Visit 9 prior to study unblinding.