Healthy ParticipantsPhase 1NCT07122986
A Study to Learn About a Vaccine Against E Coli in Healthy Adults
A Phase 1 study testing E coli vaccine 1 Dose A, E coli vaccine 1 Dose B and E coli vaccine 2 in people with Healthy Participants, run by Pfizer at 11 sites in United States.
Trial summary
This study evaluates an investigational vaccine designed to protect against Escherichia coli (E coli). The primary objective is to assess the safety and tolerability of E coli vaccines administered intramuscularly to healthy adults. Read more about this study
- Who is it for?
- Ages 18 to 64 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Participants
- What is being tested?
- E coli vaccine 1 Dose A, E coli vaccine 1 Dose B and E coli vaccine 2
- Type of treatment
- Vaccines
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 200 participants
- Where
- 11 sitesUnited States
- Study dates
- 11 Aug 2025to 8 May 2028
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 64 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adult Participants >= 18 through < 64 years of age at the time of enrollment.
- Healthy participants as determined by medical history, physical examination, and clinical judgement of the investigator to be eligible for inclusion in the study.
Who cannot join
- Severe adverse reaction history associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).
- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
- Women who are pregnant, plan to become pregnant during the study, or are breastfeeding.
Trial locations and contacts
11 sites in 1 country.
11 sites in 1 country
United States11 sites
Anaheim Clinical Trials, LLC
Anaheim, California, 92801
CTI Clinical Research Center
Cincinnati, Ohio, 45212
Miami Eye Institute
Hollywood, Florida, 33024
Research Centers of America
Hollywood, Florida, 33024
Alliance for Multispecialty Research, LLC
Knoxville, Tennessee, 37909
Alliance for Multispecialty Research, LLC
Knoxville, Tennessee, 37920
Orange County Research Center
Lake Forest, California, 92630
University Eye Specialists, P.C. (Ophthalmologist)
Maryville, Tennessee, 37803
NYU Langone Health
New York, New York, 10016
Senders Pediatrics
South Euclid, Ohio, 44121
Diablo Clinical Research, Inc.
Walnut Creek, California, 94598
About this study
Official title: A PHASE 1, RANDOMIZED, DOUBLE-BLIND, THIRD-PARTY-UNBLINDED STUDY TO EVALUATE THE SAFETY AND TOLERABILITY OF A VACCINE AGAINST E COLI IN HEALTHY ADULTS
This study evaluates an investigational vaccine designed to protect against Escherichia coli (E coli). The primary objective is to assess the safety and tolerability of E coli vaccines administered intramuscularly to healthy adults.
- Conditions
- Healthy Participants
- Being tested
- E coli vaccine 1 Dose A, E coli vaccine 1 Dose B, E coli vaccine 2, E coli vaccine 3, E coli Vaccine 4 Dose A
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
E coli vaccine 1 Dose ADrug
Candidate E coli vaccine 1 Dose A, administered according to a 0, 6-month interval
E coli vaccine 1 Dose BDrug
Candidate E coli vaccine 1 Dose B, administered according to a 0, 6-month interval
E coli vaccine 2Drug
Candidate E coli vaccine 2, administered according to a 0, 6-month interval
E coli vaccine 3Drug
Candidate E coli vaccine 3, administered according to a 0, 6-month interval
E coli Vaccine 4 Dose ADrug
Candidate E coli vaccine 4 Dose A, administered according to a 0, 6-month interval
E coli Vaccine 4 Dose BDrug
Candidate E coli vaccine 4 Dose B, administered according to a 0, 6-month interval
E coli Vaccine 4 Dose CDrug
Candidate E coli vaccine 4 Dose C, administered according to a 0, 6-month interval
E coli Vaccine 5 Dose ADrug
Candidate E coli vaccine 5 Dose A, administered according to a 0, 6-month interval
E coli Vaccine 5 Dose BDrug
Candidate E coli vaccine 5 Dose B, administered according to a 0, 6-month interval
PlaceboDrug
Placebo administered according to a 0, 6-month interval
| Study group | Role | What they receive |
|---|---|---|
| E coli vaccine 1 Dose A | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli vaccine 1 Dose A |
| E coli vaccine 1 Dose B | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli vaccine 1 Dose B |
| E coli vaccine 2 | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli vaccine 2 |
| E coli vaccine 3 | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli vaccine 3 |
| E coli Vaccine 4 Dose A | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli Vaccine 4 Dose A |
| E coli Vaccine 4 Dose B | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli Vaccine 4 Dose B |
| E coli Vaccine 4 Dose C | Experimental | Candidate E coli vaccine on day 1 and day 180 Receives: Drug: E coli Vaccine 4 Dose C |
| E coli Vaccine 5 Dose A | Experimental | Not described Receives: Drug: E coli Vaccine 5 Dose A |
| E coli Vaccine 5 Dose B | Experimental | Not described Receives: Drug: E coli Vaccine 5 Dose B |
| Placebo | Experimental | Placebo received on day 1 and day 180 Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of participants reporting prespecified local events within 7 days following each vaccination
Prespecified local reactions (redness, swelling, and pain at the injection site) following each vaccination
Measured: 7 days after each vaccination
Percentage of participants reporting prespecified systemic events within 7 days following each vaccination
Prespecified systemic events (fever, fatigue, headache, chills, vomiting, diarrhea, joint pain, and muscle pain) following each vaccination
Measured: 7 days after each vaccination
Percentage of participants reporting Adverse Events (AEs) from vaccination 1 through 1 month after the last dose of study intervention
Adverse events occurring up to 1 month after the last dose of study intervention
Measured: From signing of ICD to 1 month after the last assigned vaccination
Percentage of participants reporting Medically Attended Adverse Events (MAEs) from vaccination 1 through 12 months after the last dose of study intervention
MAEs occurring up to 12 months after the last dose of study intervention
Measured: Baseline up to month 18 with final visit being 12 months after last assigned vaccination
Percentage of participants reporting Serious Adverse Events (SAEs) from vaccination 1 through 12 months after the last dose of study intervention
SAEs occurring up to 12 months after the last dose of study intervention
Measured: Baseline up to month 18 with final visit being 12 months after last assigned vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Aug 2025
- Study start11 Aug 2025
- Primary completion8 May 2028 (estimated)
- Study completion8 May 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy ParticipantsStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Care provider
- Enrolment
- 200 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07122986
- Sponsor's protocol ID
- C5211001
- Status last verified
- Oct 2026
- First submitted
- 7 Aug 2025
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A PHASE 1, RANDOMIZED, DOUBLE-BLIND, THIRD-PARTY-UNBLINDED STUDY TO EVALUATE THE SAFETY AND TOLERABILITY OF A VACCINE AGAINST E COLI IN HEALTHY ADULTS
- ClinicalTrials.gov ID
- NCT07122986
- Acronym / sponsor ID
- C5211001
- Conditions
- Healthy Participants
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 200 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 11 Aug 2025 (actual)
- Primary completion
- 8 May 2028 (estimated)
- Study completion
- 8 May 2028 (estimated)
- First posted
- 14 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluates an investigational vaccine designed to protect against Escherichia coli (E coli). The primary objective is to assess the safety and tolerability of E coli vaccines administered intramuscularly to healthy adults.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, care provider)
- Number of arms
- 10
| Arm | Type | Receives |
|---|---|---|
| E coli vaccine 1 Dose A | Experimental | Drug: E coli vaccine 1 Dose ACandidate E coli vaccine on day 1 and day 180 |
| E coli vaccine 1 Dose B | Experimental | Drug: E coli vaccine 1 Dose BCandidate E coli vaccine on day 1 and day 180 |
| E coli vaccine 2 | Experimental | Drug: E coli vaccine 2Candidate E coli vaccine on day 1 and day 180 |
| E coli vaccine 3 | Experimental | Drug: E coli vaccine 3Candidate E coli vaccine on day 1 and day 180 |
| E coli Vaccine 4 Dose A | Experimental | Drug: E coli Vaccine 4 Dose ACandidate E coli vaccine on day 1 and day 180 |
| E coli Vaccine 4 Dose B | Experimental | Drug: E coli Vaccine 4 Dose BCandidate E coli vaccine on day 1 and day 180 |
| E coli Vaccine 4 Dose C | Experimental | Drug: E coli Vaccine 4 Dose CCandidate E coli vaccine on day 1 and day 180 |
| E coli Vaccine 5 Dose A | Experimental | Drug: E coli Vaccine 5 Dose A |
| E coli Vaccine 5 Dose B | Experimental | Drug: E coli Vaccine 5 Dose B |
| Placebo | Experimental | Drug: PlaceboPlacebo received on day 1 and day 180 |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Adult Participants >= 18 through < 64 years of age at the time of enrollment.
- Healthy participants as determined by medical history, physical examination, and clinical judgement of the investigator to be eligible for inclusion in the study.
Key exclusion criteria (3 listed)
- Severe adverse reaction history associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).
- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
- Women who are pregnant, plan to become pregnant during the study, or are breastfeeding.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| E coli vaccine 1 Dose ACandidate E coli vaccine 1 Dose A, administered according to a 0, 6-month interval | Drug | E coli vaccine 1 Dose A |
| E coli vaccine 1 Dose BCandidate E coli vaccine 1 Dose B, administered according to a 0, 6-month interval | Drug | E coli vaccine 1 Dose B |
| E coli vaccine 2Candidate E coli vaccine 2, administered according to a 0, 6-month interval | Drug | E coli vaccine 2 |
| E coli vaccine 3Candidate E coli vaccine 3, administered according to a 0, 6-month interval | Drug | E coli vaccine 3 |
| E coli Vaccine 4 Dose ACandidate E coli vaccine 4 Dose A, administered according to a 0, 6-month interval | Drug | E coli Vaccine 4 Dose A |
| E coli Vaccine 4 Dose BCandidate E coli vaccine 4 Dose B, administered according to a 0, 6-month interval | Drug | E coli Vaccine 4 Dose B |
| E coli Vaccine 4 Dose CCandidate E coli vaccine 4 Dose C, administered according to a 0, 6-month interval | Drug | E coli Vaccine 4 Dose C |
| E coli Vaccine 5 Dose ACandidate E coli vaccine 5 Dose A, administered according to a 0, 6-month interval | Drug | E coli Vaccine 5 Dose A |
| E coli Vaccine 5 Dose BCandidate E coli vaccine 5 Dose B, administered according to a 0, 6-month interval | Drug | E coli Vaccine 5 Dose B |
| PlaceboPlacebo administered according to a 0, 6-month interval | Drug | Placebo |
Primary outcome
Percentage of participants reporting prespecified local events within 7 days following each vaccination
Time frame: 7 days after each vaccination
Prespecified local reactions (redness, swelling, and pain at the injection site) following each vaccination
Percentage of participants reporting prespecified systemic events within 7 days following each vaccination
Time frame: 7 days after each vaccination
Prespecified systemic events (fever, fatigue, headache, chills, vomiting, diarrhea, joint pain, and muscle pain) following each vaccination
Percentage of participants reporting Adverse Events (AEs) from vaccination 1 through 1 month after the last dose of study intervention
Time frame: From signing of ICD to 1 month after the last assigned vaccination
Adverse events occurring up to 1 month after the last dose of study intervention
Percentage of participants reporting Medically Attended Adverse Events (MAEs) from vaccination 1 through 12 months after the last dose of study intervention
Time frame: Baseline up to month 18 with final visit being 12 months after last assigned vaccination
MAEs occurring up to 12 months after the last dose of study intervention
Percentage of participants reporting Serious Adverse Events (SAEs) from vaccination 1 through 12 months after the last dose of study intervention
Time frame: Baseline up to month 18 with final visit being 12 months after last assigned vaccination
SAEs occurring up to 12 months after the last dose of study intervention
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: No. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
11 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing E coli vaccine 1 Dose A, E coli vaccine 1 Dose B and E coli vaccine 2 in people with Healthy Participants, run by Pfizer at 11 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 27 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 11 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of participants reporting prespecified local events within 7 days following each vaccination (time frame: 7 days after each vaccination). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Oct 2026.