Pfizer launches massive trial of c. diff vaccine for seniors

NCT ID NCT07282665

Vaccine Sponsor: Pfizer Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Sep 10, 2026 · Updated 3 times

Summary

This study tests whether a vaccine can prevent C. difficile infection in adults 65 and older. About 32,000 participants will receive either the vaccine or a placebo shot. The study will track infections and side effects over up to three and a half years.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

About 32,500 people

The number the study aims to enrol. It can still change while the study runs.

Started

Dec 2025

Expected to finish

Jun 2029

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

65 years and older

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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.

Get updates

Get notified about this study

Sign up to get updates when this study changes or when new studies for Clostridioides difficile associated disease are added.

Vår säkerhetsrekommendation!

Genom att skicka in godkänner du våra Användarvillkor

Conditions

The condition(s) this trial relates to.

Clostridium difficile colitis prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Clostridioides difficile associated disease Clostridoides difficile associated disease

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

184 sites in 4 countries. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

Open the record ↗
A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

AMR Clinical
RECRUITING

Newton, Kansas, 67114, United States
Accellacare - Cary
RECRUITING

Cary, North Carolina, 27518, United States
Accellacare - Hickory
RECRUITING

Hickory, North Carolina, 28601, United States
Accellacare - McFarland
RECRUITING

Ames, Iowa, 50010, United States
Accellacare - Raleigh
RECRUITING

Raleigh, North Carolina, 27609, United States
Accellacare - Salisbury
RECRUITING

Salisbury, North Carolina, 28144, United States
Accellacare - Wilmington
RECRUITING

Wilmington, North Carolina, 28401, United States
Accellacare - Winston-Salem
RECRUITING

Winston-Salem, North Carolina, 27103, United States
Albuquerque Clinical Trials, Inc.
RECRUITING

Albuquerque, New Mexico, 87102, United States
Angels Clinical Research Institute
RECRUITING

Tampa, Florida, 33614, United States
Applied Research Center of Arkansas
RECRUITING

Little Rock, Arkansas, 72205, United States
Aso Iizuka Hospital
RECRUITING

Iizuka-shi, Fukuoka, 820-8505, Japan
Atlanta VA Medical Center
RECRUITING

Decatur, Georgia, 30033, United States
Atrium Health Wake Forest Baptist Infectious Disease-High Point
RECRUITING

High Point, North Carolina, 27262, United States
Bay Pines VA Healthcare System
RECRUITING

Bay Pines, Florida, 33744, United States
Baylor College of Medicine
RECRUITING

Houston, Texas, 77030, United States
Brunel Medical Practice (St Marychurch)
RECRUITING

Torquay, Devon, TQ1 4QX, United Kingdom
CDC Centro Médico
RECRUITING

Lujan de Cuyo, Mendoza Province, 5505, Argentina
CTI Clinical Research Center
RECRUITING

Cincinnati, Ohio, 45212, United States
Capital Area Research, LLC
RECRUITING

Camp Hill, Pennsylvania, 17011, United States
Carbon Health - San Mateo - Hillsdale Mall
ACTIVE_NOT_RECRUITING

San Mateo, California, 94403, United States
Care Research Inc
RECRUITING

Miami, Florida, 33130, United States
Cedar Health Research - Euless
RECRUITING

Euless, Texas, 76040, United States
Centricity Research Columbus Georgia Multispecialty
RECRUITING

Columbus, Georgia, 31904, United States
Centro Medico Barrio Parque
RECRUITING

Buenos Aires, 1425, Argentina
Charisma Medical and Research Center
RECRUITING

Miami Lakes, Florida, 33014, United States
Cheadle Community Hospital
RECRUITING

Cheadle, Staffordshire, ST10 1NS, United Kingdom
Chinle Center for Indigenous Health
RECRUITING

Chinle, Arizona, 86503, United States
Chinle Comprehensive Health Care Facility
RECRUITING

Chinle, Arizona, 86503, United States
Clinica Del Niño Y La Madre
RECRUITING

Mar del Plata, Buenos Aires, 7600, Argentina
Clinica Mayo de Urgencias Médicas Cruz Blanca S.R.L
NOT_YET_RECRUITING

San Miguel de Tucumán, Tucumán Province, 4000, Argentina
Clinica Privada del Sol S.A
RECRUITING

Córdoba, Córdoba Province, X5000IIH, Argentina
Clinical Neuroscience Solutions, LLC
RECRUITING

Jacksonville, Florida, 32256, United States
Clinical Neuroscience Solutions, LLC
RECRUITING

Memphis, Tennessee, 38119, United States
Clinical Research Partners, LLC
RECRUITING

Richmond, Virginia, 23226, United States
Columbia University Irving Medical Center
RECRUITING

New York, New York, 10032, United States
DM Clinical Research - Chicago
RECRUITING

Melrose Park, Illinois, 60160, United States
DM Clinical Research - Detroit
RECRUITING

Southfield, Michigan, 48076, United States
DM Clinical Research - Philadelphia
RECRUITING

Philadelphia, Pennsylvania, 19107, United States
DM Clinical Research- Cyfair
RECRUITING

Houston, Texas, 77065, United States
Diablo Clinical Research, Inc.
RECRUITING

Walnut Creek, California, 94598, United States
Duke University Health System
RECRUITING

Raleigh, North Carolina, 27609, United States
Duke University Health System-Duke Vaccine and Trials Unit Raleigh
RECRUITING

Raleigh, North Carolina, 27609, United States
Duke Vaccine and Trials Unit
RECRUITING

Durham, North Carolina, 27703, United States
Dynamed Clinical Research, LP d/b/a DM Clinical Research
RECRUITING

Tomball, Texas, 77375, United States
Emory Steiner Building Research Center
RECRUITING

Atlanta, Georgia, 30303, United States
Emory University Woodruff Extension Building (WEB)
RECRUITING

Atlanta, Georgia, 30303, United States
Entrust Clinical Research
RECRUITING

Miami, Florida, 33176, United States
Epic Medical Research-Sun City
RECRUITING

Sun City, Arizona, 85351, United States
Equipo Ciencia
RECRUITING

Buenos Aires, Buenos Aires F.D., C1428BNF, Argentina
Family Health Watch - KeyPoint Clinical Research
RECRUITING

Dallas, Texas, 75237, United States
Fukuoka Shinmizumaki Hospital
RECRUITING

Onga-gun, Fukuoka, 807-0051, Japan
Fundación Huésped
RECRUITING

Buenos Aires, Buenos Aires F.D., 1427, Argentina
GW Vaccine Research Unit
RECRUITING

Washington D.C., District of Columbia, 20037, United States
Gallup Center for Indigenous Health
RECRUITING

Gallup, New Mexico, 87301, United States
Gallup Indian Medical Center
RECRUITING

Gallup, New Mexico, 87301, United States
HMH David Jurist Research Building
RECRUITING

Hackensack, New Jersey, 07601, United States
HMH Hackensack University Medical Center
RECRUITING

Hackensack, New Jersey, 07601, United States
HOPE Tower at Jersey Shore University Medical Center
RECRUITING

Neptune City, New Jersey, 07753, United States
Hackensack Meridian Health Hackensack University Medical Center
RECRUITING

Hackensack, New Jersey, 07601, United States
Hackensack Meridian Health Jersey Shore University Medical Center
RECRUITING

Neptune City, New Jersey, 07753, United States
Hospital de Clinicas Presidente Nicolas Avellaneda
NOT_YET_RECRUITING

San Miguel de Tucumán, Tucumán Province, 4000, Argentina
Icahn School of Medicine at Mount Sinai
RECRUITING

New York, New York, 10029, United States
Indago Research & Health Center, Inc
RECRUITING

Miami Lakes, Florida, 33016, United States
Instituto Médico Platense (IMP)
RECRUITING

La Plata, Buenos Aires, 1900, Argentina
Investigaciones Clínicas Salta (ICSAL)
RECRUITING

Salta, A4400, Argentina
J. Lewis Research, Inc. / Foothill Family Clinic South
RECRUITING

Salt Lake City, Utah, 84121, United States
James J. Peters VA Medical Center
RECRUITING

The Bronx, New York, 10468, United States
Japan Community Healthcare Organization Kyushu Hospital
RECRUITING

Kitakyushu-shi, Fukuoka, 806-8501, Japan
Japanese Red Cross Kumamoto Hospital
RECRUITING

Kumamoto, Kumamoto, 861-8520, 862-8520, Japan
Johns Hopkins Bloomberg School of Public Health
RECRUITING

Baltimore, Maryland, 21205, United States
Johns Hopkins Bloomberg School of Public Health
RECRUITING

Baltimore, Maryland, 21231, United States
Kaiser Permanente - San Diego Medical Center
RECRUITING

San Diego, California, 92123, United States
Kaiser Permanente Center for Health Research
RECRUITING

Portland, Oregon, 97227, United States
Kaiser Permanente Daly City
RECRUITING

Daly City, California, 94015, United States
Kaiser Permanente Los Angeles Medical Center
RECRUITING

Los Angeles, California, 90027, United States
Kaiser Permanente Oakland
RECRUITING

Oakland, California, 94611, United States
Kaiser Permanente Oncology Pharmacy #014C
RECRUITING

Los Angeles, California, 90027, United States
Kaiser Permanente Ontario Medical Center
RECRUITING

Ontario, California, 91761, United States
Kaiser Permanente Roseville
RECRUITING

Roseville, California, 95661, United States
Kaiser Permanente Sacramento
RECRUITING

Sacramento, California, 95815, United States
Kaiser Permanente San Jose
RECRUITING

San Jose, California, 95119, United States
Kaiser Permanente Santa Clara
RECRUITING

Santa Clara, California, 95051, United States
Kaiser Permanente South Sacramento
RECRUITING

Sacramento, California, 95823, United States
Kaiser Permanente Viewridge Medical Office
RECRUITING

San Diego, California, 92123, United States
Kaiser Permanente Walnut Creek
RECRUITING

Walnut Creek, California, 94596, United States
Kaiser Permanente Washington Health Research Institute (KPWHRI)
RECRUITING

Seattle, Washington, 98101, United States
Kamiiida daiichi General Hospital
RECRUITING

Nagoya, Aichi-ken, 462-0802, Japan
KeyPoint Clinical Research
RECRUITING

Dallas, Texas, 75240, United States
Knowle House Surgery
RECRUITING

Plymouth, Devon, PL5 3JB, United Kingdom
Koga General Hospital
RECRUITING

Koga, Ibaraki, 306-0041, Japan
Kojunkai Daido Clinic
RECRUITING

Nagoya, Aichi-ken, 457-8511, Japan
Lakeside Surgery
RECRUITING

Corby, Northamptonshire, NN17 2UR, United Kingdom
Lakeview Clinical Research
RECRUITING

Guntersville, Alabama, 35976, United States
Layton Medical Centre
RECRUITING

Blackpool, Lancashire, FY3 7EN, United Kingdom
M3 Wake Research - Lake City
RECRUITING

Lake City, Florida, 32055, United States
Manchester Royal Infirmary
RECRUITING

Manchester, M13 9WU, United Kingdom
McFarland Clinic, PC
RECRUITING

Ames, Iowa, 50010, United States
Med Partners, Inc. dba Premiere Medical Center of Burbank, Inc.
RECRUITING

Toluca Lake, California, 91602, United States
Medical Affiliated Research Center
RECRUITING

Huntsville, Alabama, 35801, United States
Medication Management
RECRUITING

Greensboro, North Carolina, 27405, United States
Memorial Hermann Hospital - TMC
RECRUITING

Houston, Texas, 77030, United States
Mercury Clinical Research - Santa Clara Family Clinic
RECRUITING

Houston, Texas, 77087, United States
Montefiore Medical Center
RECRUITING

The Bronx, New York, 10467, United States
Mount Sinai Morningside
RECRUITING

New York, New York, 10025, United States
Mount Sinai Queens
RECRUITING

Long Island City, New York, 11102, United States
Mount Sinai West
RECRUITING

New York, New York, 10019, United States
NYU Langone Health
RECRUITING

Brooklyn, New York, 11220, United States
NYU Langone Health
RECRUITING

Mineola, New York, 11501, United States
NYU Langone Health
RECRUITING

New York, New York, 10016, United States
Nanbu Tokushukai Hospital
RECRUITING

Shimajiri, Okinawa, 901-0417, Japan
National Center for Global Health and Medicine
RECRUITING

Shinjuku, Tokyo, 162-8655, Japan
National Hospital Organization Nagasaki Medical Center
RECRUITING

Ōmura, Nagasaki, 856-8562, Japan
New Phase Research and Development
RECRUITING

Knoxville, Tennessee, 37909, United States
Newquay Health Centre
RECRUITING

Newquay, Cornwall, TR7 1RU, United Kingdom
North Alabama Research Center
RECRUITING

Athens, Alabama, 35611, United States
North Shore University Hospital
RECRUITING

Manhasset, New York, 11030, United States
North Texas Infectious Diseases Consultants, P.A
RECRUITING

Dallas, Texas, 75246, United States
North Wales Clinical Research Facility
NOT_YET_RECRUITING

Wrexham, Wrexham [wrecsam Gb-wrc], LL13 7YP, United Kingdom
Northern Navajo Medical Center
RECRUITING

Shiprock, New Mexico, 87420, United States
Northern Westchester Hospital
RECRUITING

Mount Kisco, New York, 10549, United States
Northwell Health Infectious Disease
RECRUITING

Manhasset, New York, 11030, United States
Northwest Houston Heart Center
RECRUITING

Tomball, Texas, 77375, United States
Nozaki Tokushukai Hospital
RECRUITING

Daitō, Osaka, 574-0074, Japan
Ochsner Lafayette General Medical Center
RECRUITING

Lafayette, Louisiana, 70503, United States
Ochsner Medical Complex - The Grove
RECRUITING

Baton Rouge, Louisiana, 70836, United States
Ormeau Clinical Trials
RECRUITING

Belfast, Northern Ireland, BT2 8BG, United Kingdom
Palm Springs Community Health Center
RECRUITING

Miami Lakes, Florida, 33014, United States
Panthera Biopartners - Glasgow
RECRUITING

Glasgow, G51 4RY, United Kingdom
Panthera Biopartners - Manchester
RECRUITING

Rochdale, Manchester, OL11 4AU, United Kingdom
Panthera Biopartners - Preston
RECRUITING

Preston, England, PR2 9QB, United Kingdom
Panthera Biopartners - Sheffield
RECRUITING

Sheffield, S2 5FX, United Kingdom
Panthera Clinic - York
RECRUITING

York, North Yorkshire, YO24 4LJ, United Kingdom
Phelps Hospital Geriatric Medicine & Improvement Science
RECRUITING

Sleepy Hollow, New York, 10591, United States
Proactive Clinical Research,LLC
RECRUITING

Fort Lauderdale, Florida, 33308, United States
Providence Regional Medical Center Everett
RECRUITING

Everett, Washington, 98201, United States
Raleigh Medical Group P.A.
RECRUITING

Raleigh, North Carolina, 27609, United States
Renown Center for Advanced Medicine
RECRUITING

Reno, Nevada, 89502, United States
Renown Regional Medical Center
RECRUITING

Reno, Nevada, 89502, United States
Revive Research Institute, Inc.
RECRUITING

Southfield, Michigan, 48075, United States
Rochester Clinical Research, LLC
RECRUITING

Rochester, New York, 14609, United States
Royal Devon & Exeter Hospital
RECRUITING

Exeter, Devon, EX2 5DW, United Kingdom
Rutgers Robert Wood Johnson Medical School
RECRUITING

New Brunswick, New Jersey, 08901, United States
Sacramento VA Medical Center
RECRUITING

Mather, California, 95655, United States
Saga University Hospital
RECRUITING

Saga, Saga-ken, 849-8501, Japan
Sanatorio Sagrado Corazón
RECRUITING

Buenos Aires, 1039, Argentina
Seishinkai Inoue Hospital
RECRUITING

Itoshima, Fukuoka, 819-1104, Japan
Shiprock Center for Indigenous Health
RECRUITING

Shiprock, New Mexico, 87420, United States
South Florida Research Organization
RECRUITING

Medley, Florida, 33166, United States
South Jersey Infectious Disease
RECRUITING

Somers Point, New Jersey, 08244, United States
Southampton General Hospital
RECRUITING

Southampton, Hampshire, SO16 6YD, United Kingdom
Staten Island University Hospital
RECRUITING

Staten Island, New York, 10305, United States
Sundance Clinical Research
RECRUITING

St Louis, Missouri, 63141, United States
Synexus Manchester Clinical Research Centre
RECRUITING

Manchester, M15 6SE, United Kingdom
Synexus Midlands Clinical Research Centre
RECRUITING

Birmingham, B16 8QQ, United Kingdom
Synexus Scotland Clinical Research Centre
NOT_YET_RECRUITING

Glasgow, Glasgow CITY, ML4 3NJ, United Kingdom
The GW Medical Faculty Associates
RECRUITING

Washington D.C., District of Columbia, 20037, United States
The Hope Clinic of Emory University
RECRUITING

Decatur, Georgia, 30030, United States
The University of Texas Health Science Center at Houston
RECRUITING

Houston, Texas, 77030, United States
The University of Vermont Medical Center Inc.
RECRUITING

Burlington, Vermont, 05401, United States
The Vanderbilt Vaccine Research Program Clinic at The Village at Vanderbilt
RECRUITING

Nashville, Tennessee, 37212, United States
Tokyo-Eki Center-building Clinic
RECRUITING

Chuo-ku, Tokyo, 103-0027, Japan
UT Physicians
RECRUITING

Houston, Texas, 77030, United States
UVM Larner College of Medicine MMG/VCT
RECRUITING

Burlington, Vermont, 05401, United States
University Health
RECRUITING

Reno, Nevada, 89519, United States
University Of Nebraska Medical Center
RECRUITING

Omaha, Nebraska, 68198, United States
University of Nebraska Medical Center
RECRUITING

Omaha, Nebraska, 68105, United States
University of Washington - Harborview Medical Center
RECRUITING

Seattle, Washington, 98104, United States
Upstate Global Health Institute
RECRUITING

East Syracuse, New York, 13057, United States
VA Boston Healthcare System - West Roxbury
RECRUITING

West Roxbury, Massachusetts, 02132, United States
VA Northeast Ohio Healthcare System Louis Stokes Cleveland VA Medical Center
RECRUITING

Cleveland, Ohio, 44106, United States
Vanderbilt Investigational Drug Service (IDS)
RECRUITING

Nashville, Tennessee, 37232, United States
Vanderbilt University Medical Center
RECRUITING

Nashville, Tennessee, 37232, United States
Vanderbilt Vaccine Research Program
RECRUITING

Nashville, Tennessee, 37232, United States
Vanderbilt Vaccine Research Program Laboratory
RECRUITING

Nashville, Tennessee, 37232, United States
Velocity Clinical Research, Grand Island
RECRUITING

Grand Island, Nebraska, 68803, United States
Velocity Clinical Research, Omaha
RECRUITING

Omaha, Nebraska, 68134, United States
Velocity Clinical Research, San Bernardino
RECRUITING

San Bernardino, California, 92408, United States
Velocity Clinical Research, Savannah
RECRUITING

Savannah, Georgia, 31406, United States
Velocity Clinical Research, Sioux City
RECRUITING

Sioux City, Iowa, 51106, United States
Velocity Clinical Research, Spartanburg
RECRUITING

Spartanburg, South Carolina, 29303, United States
Wake Forest Baptist Health
RECRUITING

Winston-Salem, North Carolina, 27157, United States
Walker Family Care
RECRUITING

Little River, South Carolina, 29566, United States
Washington University School of Medicine
RECRUITING

St Louis, Missouri, 63110, United States
Wilmington Health, PLLC
RECRUITING

Wilmington, North Carolina, 28401, United States

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