DysenteryPhase 3NCT06838195
Clinical Trial of the S. Flexneri-S. Sonnei Bivalent Conjugate Vaccine
A Phase 3 study testing S. Flexneri-S. Sonnei bivalent conjugate vaccine in people with Dysentery and Dysentery, Shigella, run by Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd at 1 site in Bangladesh.
Trial summary
The goal of this clinical trial is to evaluate the protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine against diarrhea caused by Shigella infection in infants and children aged 6 months to 5 years. Read more about this study
- Who is it for?
- Ages 6 months to 5 yearsHealthy volunteers can take part
- Conditions the study is for
- Dysentery, Dysentery, Shigella
- What is being tested?
- S. Flexneri-S. Sonnei bivalent conjugate vaccine
- Type of treatment
- Vaccines
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 8,000 participants
- Where
- 1 siteBangladesh
- Study dates
- 12 May 2025to 30 Jul 2028
- Phase
- Phase 3
- 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 6 months to 5 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Infants and children aged 6 months to 5 years.
- Legal guardians voluntarily agree to participate in the study and sign an informed consent form.
- Legal guardians agree to comply with the requirements of the clinical trial protocol and are willing and able to participate in all planned follow-ups.
- The subject's guardian agrees that the subject should not abuse antibiotics. If needed，antibiotics should be used under the guidance of a doctor and avoid taking antibiotics on their own during the clinical trial.
- Based on medical history, physical examination, and the investigator's judgment, the subject is determined to be in good health.
Who cannot join
- History of confirmed bacterial dysentery in the past 6 months.
- Serious allergy to tetanus toxoid, history of severe allergies, fever above 39.5°C following previous vaccination with a prophylactic biological product.
- Currently suffering from serious intestinal diseases, symptoms of diarrhea, abdominal pain, or bloody purulent stools in the past 15 days.
- Diagnosed pathological jaundice currently.
- Confirmed diagnosis of thrombocytopenia or other coagulation disorders.
- Known or suspected immunological deficiencies (e.g., perianal abscesses indicating potential immune deficiency in infants and young children), long-term treatment (≥14 days) with immunosuppressants within half a year before vaccination (radiotherapy, chemotherapy, systemic corticosteroids ≥2 mg/kg/day, antimetabolites, cytotoxic drugs), or parents confirmed to have HIV infection.
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- Receipt of immunoglobulins/blood products (except hepatitis B immunoglobulin) within 3 months before vaccination.
- Severe congenital anomalies (important organ function impairment), severe malnutrition, developmental disorders, severe hereditary diseases.
- Currently suffering from the following diseases:
- Severe liver or kidney diseases, cardiovascular diseases, malignant tumors, and other severe chronic diseases.
- Diagnosed serious infectious diseases, such as tuberculosis, viral hepatitis, etc.
- Severe asthma.
- Generalized rashes, dermatophytosis, skin suppuration, or blistering.
- Convulsions, epilepsy, encephalopathy, psychiatric disorders or family history of psychiatric disorders.
- Planning to participate or currently participating in other vaccine or drug clinical trials.
- Any condition that the investigators believe may affect the evaluation of the study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Randomized, Double-blind, Placebo-controlled Phase III Clinical Trial Evaluating the Protective Efficacy, Immunogenicity, and Safety of the S. Flexneri-S. Sonnei Bivalent Conjugate Vaccine in Infants and Children Aged 6 Months to 5 Years in Bangladesh
The goal of this clinical trial is to evaluate the protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine against diarrhea caused by Shigella infection in infants and children aged 6 months to 5 years. Researchers will observe the incidence of diarrhea of any severity due to Shigella flexneri and Shigella sonnei infection 30 days after full immunization. The subjects will receive 2 doses of vaccination.
- Conditions
- Dysentery, Dysentery, Shigella
- Being tested
- S. Flexneri-S. Sonnei bivalent conjugate vaccine, Placebo
- Keywords
- S. Flexneri-S. Sonnei bivalent conjugate vaccine
- Medical subject headings
- Dysentery, Dysentery, Bacillary
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
S. Flexneri-S. Sonnei bivalent conjugate vaccineBiological
Subjects receive two doses of the vaccine on the day of randomisation (day 0) and day 30.
PlaceboBiological
Subjects receive two doses of the placebo on the day of randomisation (day 0) and day 30.
| Study group | Role | What they receive |
|---|---|---|
| Vaccine group | Experimental | 4000 subjects aged 6 months to 5 years are enrolled in this group. Receives: Biological: S. Flexneri-S. Sonnei bivalent conjugate vaccine |
| Placebo group | Placebo comparator | 4000 subjects aged 6 months to 5 years are enrolled in this group. Receives: Biological: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
The protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine
The efficacy will be assessed by comparing the incidence rate of laboratory-confirmed S. flexneri-associated or S. sonnei-associated diarrhea between the vaccinated group and the placebo group.
Statistical Analysis:
Protective efficacy(%)=(control group incidence (person-year incidence)- vaccine group incidence (person -year incidence))/control group incidence (person-year incidence)x100%
Measured: From day 30 post full immunization to the subsequent 24-month period.
Secondary outcomes (10)
The protective efficacy against diarrhea cases with positive bacterial culture for Shigella species
Evaluation of the protective efficacy of the vaccine against diarrhea cases with positive bacterial culture for Shigella species.
Measured: From he first dose of immunization to 24-month period post full immunization.
Positive PCR testing for Shigella species
Evaluation of diarrhea cases with positive PCR testing for Shigella species
Measured: From day 30 post full immunization to the subsequent 24-month period.
IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 1.
Subjects in immunogenicity subgroup 1, vaccine serotype-specific Shigella flexneri and Shigella sonnei IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization.
Measured: The 30th day after two doses of the vaccine.
IgG antibody concentration on day 30 post full immunization for subgroup 1.
For subjects in immunogenicity subgroup 1, vaccine serotype-specific Shigella flexneri and Shigella sonnei antibody concentration on day 30 post full immunization.
Measured: The 30th day after two doses of the vaccine.
IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 2.
For subjects in immunogenicity subgroup 2, vaccine serotype-specific Shigella flexneri and Shigella sonnei IgG antibody seroconversion (fourfold increase) rate on day 30 post the first dose, day 30 post full immunization, half a year after the first immunization, and one year after the first immunization.
Measured: From 30 day to 1 year after the first immunization.
IgG antibody concentration on day 30 post full immunization for subgroup 2.
For subjects in immunogenicity subgroup 2, vaccine serotype-specific Shigella flexneri and Shigella sonnei antibody concentration on day 30 post the first dose, day 30 post full immunization, half a year after the first immunization, and one year after the first immunization.
Measured: From 30 day to 1 year after the first immunization.
AEs within 0-30 minutes after vaccination
The occurrence of any adverse events within 30 minutes after each dose of vaccine (number of instances, number of cases, incidence rate, and the relationship to the vaccine administration)
Measured: Within 30 minutes after each dose of vaccine
Solicited AEs within 0-7 days after vaccination
The occurrence of solicited adverse events from Day 0 to Day 7 after each vaccine dose (number of instances, number of cases, incidence rate, and the relationship to the vaccine administration)
Measured: Within 0-7 days after each vaccine dose.
Unsolicited AEs within 0-30 days after vaccination
The occurrence of unsolicited adverse events from Day 0 to Day 30 after each vaccine dose (number of instances, number of cases, incidence rate, and the relationship to the vaccine administration).
Measured: Within 0-30 days after each vaccination
SAE within 0-6 months after primary immunization
The occurrence of Serious Adverse Events (SAEs) from after the first dose to 6 months after complete immunization (number of instances, number of cases, incidence rate, and the relationship to the vaccine administration)
Measured: Within 0-6 months after primary immunization.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2025
- Study start12 May 2025
- Primary completion2 Jul 2028 (estimated)
- Study completion30 Jul 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for DysenteryStudies of the same condition, open and under way.
- 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 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 8,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Lin Du, Study chair, Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06838195
- Sponsor's protocol ID
- PR-24079
- Status last verified
- Mar 2026
- First submitted
- 7 Feb 2025
- Last updated
- 1 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-blind, Placebo-controlled Phase III Clinical Trial Evaluating the Protective Efficacy, Immunogenicity, and Safety of the S. Flexneri-S. Sonnei Bivalent Conjugate Vaccine in Infants and Children Aged 6 Months to 5 Years in Bangladesh
- ClinicalTrials.gov ID
- NCT06838195
- Acronym / sponsor ID
- PR-24079
- Conditions
- Dysentery, Dysentery, Shigella
- Keywords
- S. Flexneri-S. Sonnei bivalent conjugate vaccine
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 8,000 participants (estimated)
- Lead sponsor
- Beijing Zhifei Lvzhu Biopharmaceutical Co., LtdIndustry (pharma, biotech, devices)
- Study start
- 12 May 2025 (actual)
- Primary completion
- 2 Jul 2028 (estimated)
- Study completion
- 30 Jul 2028 (estimated)
- First posted
- 20 Feb 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.
The goal of this clinical trial is to evaluate the protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine against diarrhea caused by Shigella infection in infants and children aged 6 months to 5 years. Researchers will observe the incidence of diarrhea of any severity due to Shigella flexneri and Shigella sonnei infection 30 days after full immunization. The subjects will receive 2 doses of vaccination.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Vaccine group | Experimental | Biological: S. Flexneri-S. Sonnei bivalent conjugate vaccine4000 subjects aged 6 months to 5 years are enrolled in this group. |
| Placebo group | Placebo comparator | Biological: Placebo4000 subjects aged 6 months to 5 years are enrolled in this group. |
Who may qualify
- Ages
- 6 months to 5 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Infants and children aged 6 months to 5 years.
- Legal guardians voluntarily agree to participate in the study and sign an informed consent form.
- Legal guardians agree to comply with the requirements of the clinical trial protocol and are willing and able to participate in all planned follow-ups.
- The subject's guardian agrees that the subject should not abuse antibiotics. If needed，antibiotics should be used under the guidance of a doctor and avoid taking antibiotics on their own during the clinical trial.
- Based on medical history, physical examination, and the investigator's judgment, the subject is determined to be in good health.
Key exclusion criteria (16 listed)
- History of confirmed bacterial dysentery in the past 6 months.
- Serious allergy to tetanus toxoid, history of severe allergies, fever above 39.5°C following previous vaccination with a prophylactic biological product.
- Currently suffering from serious intestinal diseases, symptoms of diarrhea, abdominal pain, or bloody purulent stools in the past 15 days.
- Diagnosed pathological jaundice currently.
- Confirmed diagnosis of thrombocytopenia or other coagulation disorders.
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 |
|---|---|---|
| S. Flexneri-S. Sonnei bivalent conjugate vaccineSubjects receive two doses of the vaccine on the day of randomisation (day 0) and day 30. | Biological | Vaccine group |
| PlaceboSubjects receive two doses of the placebo on the day of randomisation (day 0) and day 30. | Biological | Placebo group |
Primary outcome
The protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine
Time frame: From day 30 post full immunization to the subsequent 24-month period.
The efficacy will be assessed by comparing the incidence rate of laboratory-confirmed S. flexneri-associated or S. sonnei-associated diarrhea between the vaccinated group and the placebo group. Statistical Analysis: Protective efficacy(%)=(control group incidence (person-year incidence)- vaccine group incidence (person -year incidence))/control group incidence (person-year incidence)x100%
10 secondary outcomes
The protective efficacy against diarrhea cases with positive bacterial culture for Shigella species
Time frame: From he first dose of immunization to 24-month period post full immunization.
Positive PCR testing for Shigella species
Time frame: From day 30 post full immunization to the subsequent 24-month period.
IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 1.
Time frame: The 30th day after two doses of the vaccine.
IgG antibody concentration on day 30 post full immunization for subgroup 1.
Time frame: The 30th day after two doses of the vaccine.
IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 2.
Time frame: From 30 day to 1 year after the first immunization.
IgG antibody concentration on day 30 post full immunization for subgroup 2.
Time frame: From 30 day to 1 year after the first immunization.
AEs within 0-30 minutes after vaccination
Time frame: Within 30 minutes after each dose of vaccine
Solicited AEs within 0-7 days after vaccination
Time frame: Within 0-7 days after each vaccine dose.
Unsolicited AEs within 0-30 days after vaccination
Time frame: Within 0-30 days after each vaccination
SAE within 0-6 months after primary immunization
Time frame: Within 0-6 months after primary immunization.
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 1 Apr 2026.
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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.
Lin Du study chair
Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing S. Flexneri-S. Sonnei bivalent conjugate vaccine in people with Dysentery and Dysentery, Shigella, run by Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd at 1 site in Bangladesh.
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 5 inclusion and 16 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 1 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Bangladesh. 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. Some participants in this study may receive a placebo. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
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?
The protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine (time frame: From day 30 post full immunization to the subsequent 24-month period.). 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 1 Apr 2026.