Clinical trial NCT06838195: Clinical Trial of the S. Flexneri-S. Sonnei Bivalent Conjugate Vaccine
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
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: PHASE3
Conditions: Dysentery
Dysentery, Shigella
Keywords: S. Flexneri-S. Sonnei bivalent conjugate vaccine
Lead sponsor: Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd
Sponsor class: INDUSTRY
First posted: 2025-02-20
Enrollment: 8000
Sex: ALL
Minimum age (years): 6
Maximum age (years): 5
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

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.


Eligibility criteria: Inclusion Criteria:

* 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.

Exclusion Criteria:

* 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:

  1. Severe liver or kidney diseases, cardiovascular diseases, malignant tumors, and other severe chronic diseases.
  2. Diagnosed serious infectious diseases, such as tuberculosis, viral hepatitis, etc.
  3. Severe asthma.
  4. Generalized rashes, dermatophytosis, skin suppuration, or blistering.
  5. 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.

Primary outcomes:
measure: The protective efficacy of S. Flexneri-S. Sonnei bivalent conjugate vaccine
timeFrame: From day 30 post full immunization to the subsequent 24-month period.
Secondary outcomes:
measure: The protective efficacy against diarrhea cases with positive bacterial culture for Shigella species
timeFrame: From he first dose of immunization to 24-month period post full immunization.
measure: Positive PCR testing for Shigella species
timeFrame: From day 30 post full immunization to the subsequent 24-month period.
measure: IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 1.
timeFrame: The 30th day after two doses of the vaccine.
measure: IgG antibody concentration on day 30 post full immunization for subgroup 1.
timeFrame: The 30th day after two doses of the vaccine.
measure: IgG antibody seroconversion (fourfold increase) rate on day 30 post full immunization for subgroup 2.
timeFrame: From 30 day to 1 year after the first immunization.
measure: IgG antibody concentration on day 30 post full immunization for subgroup 2.
timeFrame: From 30 day to 1 year after the first immunization.
measure: AEs within 0-30 minutes after vaccination
timeFrame: Within 30 minutes after each dose of vaccine
measure: Solicited AEs within 0-7 days after vaccination
timeFrame: Within 0-7 days after each vaccine dose.
measure: Unsolicited AEs within 0-30 days after vaccination
timeFrame: Within 0-30 days after each vaccination
measure: SAE within 0-6 months after primary immunization
timeFrame: Within 0-6 months after primary immunization.
Other outcomes:
Locations:
city: Dhaka
country: Bangladesh
facility: Icddr,B
Study officials:
affiliation: Beijing Zhifei Lvzhu Biopharmaceutical Co., Ltd
name: Lin Du
role: STUDY_CHAIR
References: