A Phase 1/2 Randomized Study to Evaluate the Safety Tolerability Immunogenicity And Immunopersistence of a Clostridioides Difficile Vaccine Administered in a 2-Dose Regimen with Novel Adjuvants in Healthy Adults

Brief description of study

The purpose of this trial is to evaluate the safety and immune effects of an investigational vaccine in healthy volunteers ages 65 and older. This vaccine is being studied to potentially prevent severe diarrhea caused by a bacterium called Clostridioides difficile (C. diff). In hospitals, C. diff is the main cause of infectious diarrhea in the United States and, in some cases, severe infections may lead to death. Adults 65 years of age and older are at an increased risk for C. diff infection, particularly when exposed to healthcare settings. It is important to prevent C. diff infections for everyone, but especially in vulnerable groups such as older adults

The investigational C. diff vaccine that participants will be given in this study has already been given to several hundred people in previous research studies.

There will be 5 study groups. If you are eligible and agree to participate, you will be randomly assigned to 1 of 5 groups:

  • Groups 1 and 3 will receive 3 injections of the investigational vaccine and 2 injections of placebo.
  • Groups 2 and 4 will receive 2 injections of the investigational vaccine and 3 injections of placebo.
  • Group 5 will receive 3 injections of the investigational vaccine and 1 injection of placebo.
- If you decide to participate in this study, you would be asked to complete 6-11 in-person study visits over either a period of 7 months or over a 4-year period depending on the group to which you are randomized.

You may receive up to $150 for each in-person study visit and may be reimbursed for travel costs up to $51. Also, if you choose to have an additional and optional blood sample collected at three visits, you will be compensated an additional $75 at each of these visits.

Clinical Study Identifier: s24-00249

If you are registered as a volunteer, please log in to contact the study team/express interest in this study.