This study evaluates the immune response and safety of a multicomponent, 2-dose Shigella vaccine in preventing shigellosis in African infants. The candidate vaccine, altSonflex1-2-3, is currently being evaluated in a Phase 2 age de-escalation (from least vulnerable adult population to most vulnerable paediatric population) clinical study in Kenya, with the aim of identifying a preferred dose, using a 3-dose vaccination schedule in infants from 9 months of age (NCT05073003). This Phase 2 clinical study will evaluate the safety and immunogenicity of an alternative 2-dose vaccination schedule.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
200
altSonflex1-2-3 Dose A administered intramuscularly on Day 1 and Day 169
altSonflex1-2-3 Dose B administered intramuscularly on Day 1 and Day 169
altSonflex1-2-3 Dose C administered intramuscularly on Day 1 and Day 169
TYPHIBEV administered intramuscularly on Day 1
Infanrix hexa administered intramuscularly on Day 169
MR-VAC co-administered subcutaneously on Day 1 and Day 169
GSK Investigational Site
Kericho, Kenya
Geometric mean titers (GMTs) of anti-serotype-specific Shigella lipopolysaccharides/O-antigen (LPS/OAg) serum Immunoglobulin G (IgG)
Time frame: Day 1 (before administration of Dose 1)
GMTs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 169 (before administration of Dose 2)
GMTs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 29 (28 days after administration of Dose 1)
GMTs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 197 (28 days after administration of Dose 2)
Geometric mean concentrations (GMCs) of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 1 (before administration of Dose 1)
GMCs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 169 (before administration of Dose 2)
GMCs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 29 (28 days after administration of Dose 1)
GMCs of anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 197 (28 days after administration of Dose 2)
Number of infants with at least a 4-fold increase in anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 29 compared with baseline (Day 1)
Number of infants with at least a 4-fold increase in anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 197 compared with baseline (Day 1)
Number of infants with at least a 4-fold increase in anti-serotype-specific Shigella LPS/OAg serum IgG
Time frame: Day 197 compared with pre-Dose 2 (Day 169)
Number of infants with solicited administration-site events
Solicited administration site events include pain, redness and swelling at administration site.
Time frame: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
Number of infants with solicited systemic events
Solicited systemic events include fever. Fever is defined as temperature greater than or equal to (\>=) 38.0°C and preferred location for measuring temperature is the axilla.
Time frame: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
Number of infants with unsolicited adverse events (AEs)
An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events.
Time frame: During 28 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
Number of infants with serious adverse events (SAEs) during the entire study period
An SAE is defined as any untoward medical occurrence that results in death, is life threatening, requires hospitalization or prolongs existing hospitalization, results in disability/incapacity or other medically significant events.
Time frame: From Day 1 to Day 197
Number of infants with deviations from laboratory reference values of hematological, renal, and hepatic panel test results
Panel tests include measures of white blood cells, haemoglobin, platelets, neutrophils, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST).
Time frame: Day 8 compared with baseline (Day 1)
Number of infants with deviations from laboratory reference values of hematological, renal, and hepatic panel test results compared to pre-Dose 2 values
Panel tests include measures of white blood cells, haemoglobin, platelets, neutrophils, creatinine, ALT, and AST.
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Time frame: Day 176 compared with pre-Dose 2 (Day 169)
Anti-measles IgG concentrations expressed as GMCs
Time frame: At Day 1 (before the first MR-VAC vaccination) and Day 197 (28 days after the second MR-VAC vaccination)
Anti-rubella IgG concentrations expressed as GMCs
Time frame: At Day 1 (before the first MR-VAC vaccination) and Day 197 (28 days after the second MR-VAC vaccination)
Number of infants with measles seroresponse >=150 mIU/mL and >=200 mIU/mL
Time frame: At Day 197 (28 days after the second MR-VAC vaccination)
Number of infants with rubella seroresponse >=4 IU/mL and >=10 IU/mL
Time frame: Day 197 (28 days after the second MR-VAC vaccination)