Clostridioides difficile vaccine for people 65 and older

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Adults 65 and older with recent or planned contact with healthcare or recent antibiotic use are assigned to receive either an investigational C. difficile vaccine or a saline placebo by injection into the upper arm. The trial is event-driven and will continue until a predefined number of C. difficile–related diarrhea (pCDI) events occur, so individual participation averages about 3.5 years. Safety, tolerability, and the occurrence of pCDI events are monitored through planned visits and ongoing surveillance. People with prior CDI, major immunosuppression, prior C. difficile vaccines/antibodies, certain serious medical conditions, or prior intestinal resections are excluded.

Why it matters

Who can join: the full rules

Who Can Join the Study (Inclusion Criteria):

• People with recent or future planned contact with healthcare systems, recent antibiotic exposure, or a diagnosis of certain chronic medical conditions.

Who Cannot Join the Study (Exclusion Criteria):

* Anyone who has had CDI before.
* Anyone who has had surgery to remove part of their small or large intestine.
* Anyone who often has diarrhea (meaning three or more loose stools in a day, more than once a month).
* Anyone who has already received a vaccine or special antibody treatment for C. difficile.
* Anyone who has had a serious allergic reaction to a vaccine or to any part of the study vaccines.
* Anyone who might not respond well to the vaccine because their immune system is weak (either from a disease or from treatment).
* Anyone with cancer that has spread or another serious health problem.

Where it's running

• North Alabama Research Center
  Athens, Alabama, United States Recruiting
• Lakeview Clinical Research
  Guntersville, Alabama, United States Recruiting
• Medical Affiliated Research Center
  Huntsville, Alabama, United States Recruiting
• Chinle Center for Indigenous Health
  Chinle, Arizona, United States Recruiting
• Chinle Comprehensive Health Care Facility
  Chinle, Arizona, United States Recruiting
• Epic Medical Research-Sun City
  Sun City, Arizona, United States Recruiting

+135 more sites. See ClinicalTrials.gov for the full list.

Study contacts

• Study coordinator: Pfizer CT.gov Call Center
• Email: ClinicalTrials.gov_Inquiries@pfizer.com
• Phone: 1-800-718-1021

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.