C. difficile (C. diff) is a contagious bacteria and a leading cause of healthcare-related infections worldwide. This clinical trial is researching an investigational vaccine to help protect adults aged 65 and older from C. diff infection.

Study
Enroll in the C. Diff Vaccine Clinical Trial
(C. diff Vaccine Study for Adults 65+)
- Age: 65 Years and older
- Gender: All
- Condition: Clostridium difficile (C. diff) Infection
- Status: Active
The C. Diff Vaccine study is evaluating whether an investigational C. diff vaccine can safely prevent infection in adults at increased risk. There is no cost to participate.
About Clostridium difficile (C. diff)
C. difficile (C. diff) is a contagious bacteria that infects the colon (large intestine). It is the leading cause of healthcare-related infections worldwide. Symptoms may range from mild to severe and include watery diarrhea, abdominal pain and cramping, fever, nausea, and dehydration. There is currently no approved vaccine to prevent C. diff infection. Certain people are at higher risk, including adults over 65, those who have recently taken antibiotics, and those with weakened immune systems or frequent healthcare visits.
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Frequently Asked
Questions
What is C. diff?
C. difficile (C. diff) is a contagious bacteria that infects the colon (large intestine) and causes symptoms such as watery diarrhea, abdominal pain, fever, and nausea. It is the leading cause of healthcare-related infections worldwide and spreads through contact with contaminated surfaces, hands, and healthcare environments.
Who is at risk for C. diff infection?
Adults over age 65 are 10 times more likely to develop a C. diff infection than younger adults. Other risk factors include recent antibiotic use, hospitalization or frequent healthcare visits, a weakened immune system, and a prior C. diff infection.
What is the C. Diff Vaccine study?
The C. Diff Vaccine study is a clinical trial evaluating whether an investigational vaccine can safely prevent C. diff infection in adults aged 65 and older who have not previously had C. diff. Participants are randomly assigned to receive either the investigational vaccine or a placebo over two doses given approximately 6 months apart.
How long does participation in the study last?
Participation may last up to 3.5 years. In the first 18 months, you will have at least 3 in-person visits and 3 phone calls. After that, you will have one annual visit until the study ends. There is no cost to participate.
