Long-Term Immunogenicity of the altSonflex1-2-3 Shigella Vaccine in African Children

NCT07320716 | Not Yet Recruiting Phase 2 DMC

• 1 other identifier: 223136
• Study Type: interventional
• Target: 528
• Locations: 0 countries
• Sites: N/A

Brief Summary

The current study is a follow-up to 2 previous parent studies, a dose-selection study with 3 different dose-levels of the altSonflex1-2-3 vaccine in a schedule of 3 vaccinations (H06\_01TP study \[NCT05073003, 212149\]) and a study with an alternate 2 vaccination schedule H06\_02TP study \[NCT06663436, 219449\]). The current study aims to assess the longevity of the immune response to the selected dose of the altSonflex1-2-3 vaccine 1, 2, and 3 years after the last vaccination in African children. The study involves no new vaccinations but will collect immunogenicity blood samples from participants.

Conditions

Diarrhoea

Keywords

Shigella sonnei; Shigella flexneri; Shigella vaccine; altSonflex1-2-3; Shigelllosis

Outcome Measures

Primary Outcomes (3)

• Anti-serotype specific Shigella lipopolysaccharide (LPS)/O-antigen (OAg) serum immunoglobulin G (IgG), as measured by GVGH enzyme-linked immunosorbent assay . (ELISA)

  S. sonnei, S. flexneri 1b, S. flexneri 2a, and S. flexneri 3a serotypes will be tested.

  At Visit 1 of the current study (12 months after last vaccination in the parent studies)

• Anti-serotype specific Shigella LPS/OAg serum IgG, as measured by GVGH ELISA

  S. sonnei, S. flexneri 1b, S. flexneri 2a, and S. flexneri 3a serotypes will be tested.

  At Visit 2 of the current study (24 months after last vaccination in the parent studies)

• Anti-serotype specific Shigella LPS/OAg serum IgG, as measured by GVGH ELISA

  S. sonnei, S. flexneri 1b, S. flexneri 2a, and S. flexneri 3a serotypes will be tested.

  At Visit 3 of the current study (36 months after last vaccination in the parent studies)

Study Arms (4)

H06_01TP Study_Infants_Selected dose

EXPERIMENTAL

Infants who received 3 doses of the altSonflex1-2-3 vaccine on Day 1, Day 85, and Day 253 in the H06\_01TP parent study.

Biological: AltSonflex1-2-3

H06_01TP Study_ ST2_Infants_Control

ACTIVE COMPARATOR

Infants who received 2 doses of the Menveo vaccine on Day 1 and Day 85, and 1 dose of the Infanrix hexa vaccine on Day 281 in the H06\_01TP parent study.

Biological: Menveo; Biological: Infanrix hexa

H06_02TP Study_Infants_Selected dose

EXPERIMENTAL

Infants who received 2 doses of the altSonflex1-2-3 vaccine on Day 1 and Day 169 in the H06\_02TP parent study.

Biological: AltSonflex1-2-3

H06_02TP Study_ Infants_Control

ACTIVE COMPARATOR

Infants who received 1 dose of the TYPHIBEV vaccine on Day 1 and 1 dose of the Infanrix hexa vaccine on Day 169 in the H06\_02TP parent study.

Biological: Infanrix hexa; Biological: TYPHIBEV

Interventions

AltSonflex1-2-3 BIOLOGICAL

No intervention is administered in this extension study. The selected dose of altSonflex1-2-3 vaccine was administered intramuscularly in the participants' thigh during the H06\_01TP (212149) parent study on Day 1, Day 85, and Day 253; or on Day 1 and Day 169 during the H06\_02TP (219449) study.

Also known as: GSK's Shigella vaccine

H06_01TP Study_Infants_Selected dose; H06_02TP Study_Infants_Selected dose

Menveo BIOLOGICAL

No intervention is administered in this extension study. The Menveo vaccine was administered intramuscularly in the participants' thigh on Day 1 and Day 85 during the H06\_01TP (212149) parent study.

Also known as: GSKs Meningococcal A, C, Y and W-135 conjugate vaccine

H06_01TP Study_ ST2_Infants_Control

Infanrix hexa BIOLOGICAL

No intervention is administered in this extension study. The Infanrix hexa vaccine was administered intramuscularly in the participants' thigh on Day 281 during the H06\_01TP (212149) study; or on Day 169 during the H06\_02TP (219449) parent study.

Also known as: GSKs Diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis (inactivated), and Haemophilus influenzae type b vaccine

H06_01TP Study_ ST2_Infants_Control; H06_02TP Study_ Infants_Control

TYPHIBEV BIOLOGICAL

No intervention is administered in this extension study. The TYPHIBEV vaccine was administered intramuscularly in the participants' thigh on Day 1 during the H06\_02TP (219449) parent study.

Also known as: Biological E. Limiteds Typhoid Vi-CRM197 conjugate vaccine

H06_02TP Study_ Infants_Control

Eligibility Criteria

• Age: 26 Months - 55 Months
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Children who, as infants, previously participated in two completed studies (H06\_01TP or H06\_02TP) and were vaccinated with 3 or 2 doses of altSonflex1-2-3 or control vaccines, respectively, completed all previous vaccinations and are 12±1 months after the last altSonflex1-2-3 vaccination.
• Individuals in good health as determined by medical history since last study visit and clinical judgment of the investigator.

You may not qualify if:

• Serious and significant progressive, unstable, or uncontrolled clinical condition(s).
• Any confirmed or suspected immunosuppressive or immunodeficient condition.
• Clinical condition(s) representing a contraindication to blood draws.
• Any behavioural or cognitive impairment or psychiatric disease.
• Acute disease and/or fever at the time of enrollment.
• Individuals with known or suspected HIV infection or HIV-related disease, with history of an autoimmune disorder or any other known or suspected impairment/alteration of the immune system, or under immunosuppressive therapy.
• Receipt of immunoglobulins and/or any blood products or plasma derivatives, during the period starting 3 months before each study visit.

Sponsors & Collaborators

• GlaxoSmithKline: lead

MeSH Terms

Conditions

Diarrhea

Interventions

Meningococcal Vaccines; diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae b conjugate-hepatitis B vaccine; Tetanus Toxoid; Hepatitis B Vaccines

Condition Hierarchy (Ancestors)

Signs and Symptoms, Digestive; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Bacterial Vaccines; Vaccines; Biological Products; Complex Mixtures; Toxoids; Viral Hepatitis Vaccines; Viral Vaccines

Central Study Contacts

US GSK Clinical Trials Call Center

CONTACT

877-379-3718; GSKClinicalSupportHD@gsk.com

EU GSK Clinical Trials Call Center

CONTACT

+44 (0) 20 89904466; GSKClinicalSupportHD@gsk.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This is an open-label study.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 22, 2025
• First Posted: January 6, 2026
• Study Start: January 2, 2026
• Primary Completion (Estimated): October 31, 2028
• Study Completion (Estimated): October 31, 2028
• Last Updated: January 6, 2026

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or asset(s) with development terminated across all indications.
• Access Criteria: Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months, but an extension may be granted, when justified, for up to 6 months.