A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and Older
Recruiting now · Phase 3 · Has a placebo group
Conditions studied: Clostridioides Difficile Associated Disease
In brief
The purpose of the study is to learn about how effective, safe, and tolerable the Clostridioides difficile (C. difficile) vaccine is in decreasing the number of C. difficile infections (pCDI) in adults 65 years of age or older. The participants will receive either the C. difficile vaccine or placebo (saline). A placebo does not contain any active ingredients. The vaccines will be given as a shot into the upper arm muscle. This study looks at the number of diarrhea (loose stools) events related to a C. difficile infection, so the length of the study can change. If these events happen quickly, the study may finish sooner; if they happen slowly, it could take longer. Sometimes, the study might stop early if the vaccine clearly works or clearly doesn't. Participants will stay in the study until enough events have occurred to answer the main question. On average, each person is expected to take part for up to about three and a half years. During this time, participants will have 3 planned clinical visits and 3 planned phone visits. After these visits, more scheduled clinic visits will happen every year until the end of study. Besides the scheduled study visits, if at any time during the study a participant has 3 or more loose stools in 24 hours, they will be asked to save the next one (the fourth or later) and contact the study site. The study site will check to see if it could be a C. difficile infection. This check may happen at the clinic or through a phone or video call.
Key facts
- Study ID
- NCT07282665
- Run by
- Pfizer
- People needed
- 32000
- Starts
- 2025-12-10
- Expected to finish
- 2029-06-07
- Last updated by the study team
- 2026-05-26
Who can join
Age: 65 and older. Sex: any. Healthy volunteers: accepted.
Where it is running
- North Alabama Research Center — Athens, Alabama, United States (enrolling)
- Medical Affiliated Research Center — Huntsville, Alabama, United States (enrolling)
- Lakeview Clinical Research — Guntersville, Alabama, United States (enrolling)
- Applied Research Center of Arkansas — Little Rock, Arkansas, United States (enrolling)
- Kaiser Permanente Daly City — Daly City, California, United States (enrolling)
- Kaiser Permanente Los Angeles Medical Center — Los Angeles, California, United States (enrolling)
- Kaiser Permanente Oncology Pharmacy #014C — Los Angeles, California, United States (enrolling)
- Epic Medical Research-Sun City — Sun City, Arizona, United States (enrolling)
- Kaiser Permanente Oakland — Oakland, California, United States (enrolling)
- Kaiser Permanente Ontario Medical Center — Ontario, California, United States (enrolling)
- Southern California Permanente Medical Group — Pasadena, California, United States (enrolling)
- Kaiser Permanente Roseville — Roseville, California, United States (enrolling)
- Kaiser Permanente Sacramento — Sacramento, California, United States (enrolling)
- Kaiser Permanente South Sacramento — Sacramento, California, United States (enrolling)
- Velocity Clinical Research, San Bernardino — San Bernardino, California, United States (enrolling)
- Kaiser Permanente - San Diego Medical Center — San Diego, California, United States (enrolling)
- Kaiser Permanente Viewridge Medical Office — San Diego, California, United States (enrolling)
- Kaiser Permanente San Jose — San Jose, California, United States (enrolling)
- Carbon Health - San Mateo - Hillsdale Mall — San Mateo, California, United States (enrolling)
- Kaiser Permanente Santa Clara — Santa Clara, California, United States (enrolling)
- Med Partners, Inc. dba Premiere Medical Center of Burbank, Inc. — Toluca Lake, California, United States (enrolling)
- Kaiser Permanente Walnut Creek — Walnut Creek, California, United States (enrolling)
- Diablo Clinical Research, Inc. — Walnut Creek, California, United States (enrolling)
- GW Vaccine Research Unit — Washington D.C., District of Columbia, United States (enrolling)
- The GW Medical Faculty Associates — Washington D.C., District of Columbia, United States (enrolling)
Full record on ClinicalTrials.gov
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