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A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and Older
Sponsor: Pfizer
Summary
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 does not work. 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 clinic 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.
Official title: A PHASE 3, PLACEBO-CONTROLLED, DOUBLE-BLINDED, RANDOMIZED STUDY TO EVALUATE THE EFFICACY, SAFETY, AND TOLERABILITY OF A CLOSTRIDIOIDES DIFFICILE VACCINE IN ADULTS 65 YEARS OF AGE AND OLDER
Key Details
Gender
All
Age Range
65 Years - Any
Study Type
INTERVENTIONAL
Enrollment
32500
Start Date
2025-12-10
Completion Date
2029-06-07
Last Updated
2026-10-30
Healthy Volunteers
Yes
Interventions
C.difficile vaccine
C.difficile vaccine given as an intramuscular injection
Saline Placebo
0.9% sodium chloride solution given as a intramuscular injection
Locations (185)
North Alabama Research Center
Athens, Alabama, United States
Lakeview Clinical Research
Guntersville, Alabama, United States
Medical Affiliated Research Center
Huntsville, Alabama, United States
Chinle Center for Indigenous Health
Chinle, Arizona, United States
Chinle Comprehensive Health Care Facility
Chinle, Arizona, United States
Epic Medical Research-Sun City
Sun City, Arizona, United States
Applied Research Center of Arkansas
Little Rock, Arkansas, United States
Kaiser Permanente Daly City
Daly City, California, United States
Kaiser Permanente Los Angeles Medical Center
Los Angeles, California, United States
Kaiser Permanente Oncology Pharmacy #014C
Los Angeles, California, United States
Sacramento VA Medical Center
Mather, California, United States
Kaiser Permanente Oakland
Oakland, California, United States
Kaiser Permanente Ontario Medical Center
Ontario, California, United States
Kaiser Permanente Roseville
Roseville, California, United States
Kaiser Permanente Sacramento
Sacramento, California, United States
Kaiser Permanente South Sacramento
Sacramento, California, United States
Velocity Clinical Research, San Bernardino
San Bernardino, California, United States
Kaiser Permanente - San Diego Medical Center
San Diego, California, United States
Kaiser Permanente Viewridge Medical Office
San Diego, California, United States
Kaiser Permanente San Jose
San Jose, California, United States
Carbon Health - San Mateo - Hillsdale Mall
San Mateo, California, United States
Kaiser Permanente Santa Clara
Santa Clara, California, United States
Med Partners, Inc. dba Premiere Medical Center of Burbank, Inc.
Toluca Lake, California, United States
Kaiser Permanente Walnut Creek
Walnut Creek, California, United States
Diablo Clinical Research, Inc.
Walnut Creek, California, United States
GW Vaccine Research Unit
Washington D.C., District of Columbia, United States
The GW Medical Faculty Associates
Washington D.C., District of Columbia, United States
Bay Pines VA Healthcare System
Bay Pines, Florida, United States
Proactive Clinical Research,LLC
Fort Lauderdale, Florida, United States
Clinical Neuroscience Solutions, LLC
Jacksonville, Florida, United States
M3 Wake Research - Lake City
Lake City, Florida, United States
South Florida Research Organization
Medley, Florida, United States
Care Research Inc
Miami, Florida, United States
Entrust Clinical Research
Miami, Florida, United States
Charisma Medical and Research Center
Miami Lakes, Florida, United States
Palm Springs Community Health Center
Miami Lakes, Florida, United States
Indago Research & Health Center, Inc
Miami Lakes, Florida, United States
Angels Clinical Research Institute
Tampa, Florida, United States
Emory Steiner Building Research Center
Atlanta, Georgia, United States
Emory University Woodruff Extension Building (WEB)
Atlanta, Georgia, United States
Centricity Research Columbus Georgia Multispecialty
Columbus, Georgia, United States
The Hope Clinic of Emory University
Decatur, Georgia, United States
Atlanta VA Medical Center
Decatur, Georgia, United States
Velocity Clinical Research, Savannah
Savannah, Georgia, United States
DM Clinical Research - Chicago
Melrose Park, Illinois, United States
Accellacare - McFarland
Ames, Iowa, United States
McFarland Clinic, PC
Ames, Iowa, United States
Velocity Clinical Research, Sioux City
Sioux City, Iowa, United States
AMR Clinical
Newton, Kansas, United States
Ochsner Medical Complex - The Grove
Baton Rouge, Louisiana, United States
Ochsner Clinic Foundation - Kenner Clinical Trials Unit
Kenner, Louisiana, United States
Ochsner Lafayette General Medical Center
Lafayette, Louisiana, United States
Johns Hopkins Bloomberg School of Public Health
Baltimore, Maryland, United States
Johns Hopkins Bloomberg School of Public Health
Baltimore, Maryland, United States
VA Boston Healthcare System - West Roxbury
West Roxbury, Massachusetts, United States
Revive Research Institute, Inc.
Southfield, Michigan, United States
DM Clinical Research - Detroit
Southfield, Michigan, United States
Washington University School of Medicine
St Louis, Missouri, United States
Sundance Clinical Research
St Louis, Missouri, United States
Velocity Clinical Research, Grand Island
Grand Island, Nebraska, United States
University of Nebraska Medical Center
Omaha, Nebraska, United States
Velocity Clinical Research, Omaha
Omaha, Nebraska, United States
University Of Nebraska Medical Center
Omaha, Nebraska, United States
Renown Center for Advanced Medicine
Reno, Nevada, United States
Renown Regional Medical Center
Reno, Nevada, United States
University Health
Reno, Nevada, United States
Hackensack Meridian Health Hackensack University Medical Center
Hackensack, New Jersey, United States
HMH David Jurist Research Building
Hackensack, New Jersey, United States
HMH Hackensack University Medical Center
Hackensack, New Jersey, United States
Hackensack Meridian Health Jersey Shore University Medical Center
Neptune City, New Jersey, United States
HOPE Tower at Jersey Shore University Medical Center
Neptune City, New Jersey, United States
Rutgers Robert Wood Johnson Medical School
New Brunswick, New Jersey, United States
South Jersey Infectious Disease
Somers Point, New Jersey, United States
Albuquerque Clinical Trials, Inc.
Albuquerque, New Mexico, United States
Gallup Center for Indigenous Health
Gallup, New Mexico, United States
Gallup Indian Medical Center
Gallup, New Mexico, United States
Northern Navajo Medical Center
Shiprock, New Mexico, United States
Shiprock Center for Indigenous Health
Shiprock, New Mexico, United States
NYU Langone Health
Brooklyn, New York, United States
Upstate Global Health Institute
East Syracuse, New York, United States
Mount Sinai Queens
Long Island City, New York, United States
North Shore University Hospital
Manhasset, New York, United States
Northwell Health Infectious Disease
Manhasset, New York, United States
NYU Langone Health
Mineola, New York, United States
Northern Westchester Hospital
Mount Kisco, New York, United States
NYU Langone Health
New York, New York, United States
Mount Sinai West
New York, New York, United States
Mount Sinai Morningside
New York, New York, United States
Icahn School of Medicine at Mount Sinai
New York, New York, United States
Columbia University Irving Medical Center
New York, New York, United States
Rochester Clinical Research, LLC
Rochester, New York, United States
Phelps Hospital Geriatric Medicine & Improvement Science
Sleepy Hollow, New York, United States
Staten Island University Hospital
Staten Island, New York, United States
Montefiore Medical Center
The Bronx, New York, United States
James J. Peters VA Medical Center
The Bronx, New York, United States
Accellacare - Cary
Cary, North Carolina, United States
Duke Vaccine and Trials Unit
Durham, North Carolina, United States
Medication Management
Greensboro, North Carolina, United States
Accellacare - Hickory
Hickory, North Carolina, United States
Atrium Health Wake Forest Baptist Infectious Disease-High Point
High Point, North Carolina, United States