Clinical Trial of the S. Flexneri-S. Sonnei Bivalent Conjugate Vaccine

NCT06838195 | Active Not Recruiting Phase 3 DMC

• 1 other identifier: PR-24079
• Study Type: interventional
• Target: 8,000
• Locations: 1 country
• Sites: 1

Brief 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. 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

Keywords

S. Flexneri-S. Sonnei bivalent conjugate vaccine

Outcome Measures

Primary Outcomes (1)

• 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%

  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

  From he first dose of immunization to 24-month period post full immunization.

• Positive PCR testing for Shigella species

  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.

  The 30th day after two doses of the vaccine.

• IgG antibody concentration on day 30 post full immunization for subgroup 1.

  The 30th day after two doses of the vaccine.

• IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 2.

  From 30 day to 1 year after the first immunization.

Study Arms (2)

Vaccine group

EXPERIMENTAL

4000 subjects aged 6 months to 5 years are enrolled in this group.

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.

Biological: Placebo

Interventions

S. Flexneri-S. Sonnei bivalent conjugate vaccine BIOLOGICAL

Subjects receive two doses of the vaccine on the day of randomisation (day 0) and day 30.

Vaccine group

Placebo BIOLOGICAL

Subjects receive two doses of the placebo on the day of randomisation (day 0) and day 30.

Placebo group

Eligibility Criteria

• Age: 6 Months - 5 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd: lead

Study Sites (1)

Icddr,B

Dhaka, 1216, Bangladesh

Location

MeSH Terms

Conditions

Dysentery; Dysentery, Bacillary

Condition Hierarchy (Ancestors)

Gastroenteritis; Gastrointestinal Diseases; Digestive System Diseases; Intestinal Diseases; Enterobacteriaceae Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Infections

Study Officials

• Lin Du

  Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 7, 2025
• First Posted: February 20, 2025
• Study Start: May 12, 2025
• Primary Completion (Estimated): July 2, 2028
• Study Completion (Estimated): July 30, 2028
• Last Updated: April 1, 2026

Record last verified: 2026-03

Locations

BA (1)