CompletedPhase 1/2

A Study on the Safety and Immune Responses to the GVGH altSonflex1-2-3 Vaccine Against Shigellosis in Adults, Children, and Infants

Belgium, Kenya551 participantsStarted 2021-10-06

Plain-language summary

The aim of the current clinical study was to evaluate, for the first time in humans (FTIH), the safety and immunogenicity of the altSonflex1-2-3 candidate vaccine against S. sonnei and S. flexneri serotypes 1b, 2a, and 3a. The vaccine was first administered to adults 18 to 50 years of age in Europe. Subsequently, the vaccine was administered to a shigellosis-endemic population in Africa, first to adults 18 to 50 years of age, then to children 24 to 59 months of age, and finally to infants 9 months of age. Infants also received a third vaccination. Three different doses of the vaccine \[low, medium, and high amounts of antigen\] were evaluated using an age de-escalation approach (from the least vulnerable adult population to the most vulnerable paediatric population). The results of this study allowed the selection of the most appropriate dose for further vaccine development in infants 9 months of age, which was the main target age group for this vaccine.

Who can participate

Age range

9 Months – 50 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: All participants: • Participants and/or participants' parent(s)/legally acceptable representative(s) (LARs), who, in the opinion of the investigator, could and would comply with the requirements of the protocol (e.g. completion of the diary cards, return for follow-up visits). * Written or witnessed/thumb-printed informed consent was obtained from the participant/parent(s)/LAR(s) of the participant prior to the performance of any study-specific procedure. * Healthy participants, as established by medical history, clinical examination, and laboratory assessment. * Participants who satisfied all screening requirements. * Participants who were seronegative for hepatitis B and hepatitis C. * Participants who were negative for human leukocyte antigen B27 (HLA-B27). Adults 18 to 50 years of age: * A male or female between, and including, 18 and 50 years of age at the time of the first study intervention administration. * Female participants of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy or post-menopause. * Female participants of childbearing potential may be enrolled in the study, if the participant: \- has practiced adequate contraception for 1 month prior to study intervention administration, and \- has a negative pregnancy test on the day of study intervention administration, and * has agreed to c…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Stage 2: Geometric Mean Concentrations (GMCs) of Anti-serotype Specific Shigella Lipopolysaccharide (LPS)/O-Antigen (OAg) Serum Immunoglobulin G (IgG) in Participants 9 Months of Age in Africa

Timeframe: At Day 281 (28 days after the third study intervention)

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Solicited Administration Site Events

Timeframe: Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

Stage 1: Number of Adults 18 to 50 Years of Age in Europe With Solicited Systemic Events

Timeframe: Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Unsolicited Adverse Events (AEs)

Timeframe: Within 28 days after each study intervention (administered at at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Serious Adverse Events (SAEs)

Timeframe: From Day 1 to Day 113 and/or Day 197

Trial details

NCT IDNCT05073003

SponsorGlaxoSmithKline

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2025-06-24

Results submitted2025-12-22

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