This is an age-descending, randomized, placebo-controlled trial that will evaluate the safety and immunogenicity of a Trivalent Salmonella conjugate vaccine (TSCV). The trial will proceed from adults, to children, to toddlers, and then to infants.
This is an age-descending, randomized, placebo-controlled trial that will evaluate the safety and immunogenicity of a Trivalent Salmonella conjugate vaccine (TSCV). The trial will proceed from adults, to children, to toddlers, and then to infants. In Step 1A-D of the trial, participants will be randomized to receive a single dose of TSCV (Full-strength or Half-strength), Typbar-TCV, or placebo, first in adults, then in children 5 to 9 years of age, then children 24 to 59 months of age, and then 16 to 23 months of age. Participants will be followed for 6 months. After a Data Safety Monitoring Board (DSMB) review of the safety data, the trial will proceed to Step 2A and 2B whereupon 12- to 16-month-old toddlers and infants 8- to 11-months of age will be similarly and simultaneously randomized. Participants will be followed for 6 months. After another DSMB safety review, Step 3 will commence with simultaneous enrollment of 12- to 14-week-old and 16- to 18-week-old infants who will each receive a single dose of TSCV, TCV or placebo. Participants will be followed for 6 months. After a third DSMB safety review and selection of the preferred TSCV formulation (Full-strength versus Half-strength) for further clinical development (a decision taken by the Sponsor, Manufacturer, and funder, while taking into consideration the recommendation of the DSMB), Step 4 will evaluate a two-dose regimen. Infants 12 to 18 weeks of age will be randomized to receive either two doses of TSCV (at Full-strength or Half-strength, based on results from Steps 1-3) or placebo followed by Typbar-TCV. The priming dose will be administered at enrollment and the booster at \~9, \~12, or \~15-17 months of age. Participants will be followed until 6 months after the last study vaccination. Note -- Whenever investigational products are intended to be administered at a scheduled Expanded Program on Immunization visit, they will always be given 2 weeks after the routine EPI vaccines. This will not only avoid interference with EPI vaccines but will provide a convenient contact point for potential recruitment of participants for the study.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
TRIPLE
Enrollment
800
Centre for Vaccine Development (CVD-Mali)
Bamako, Mali
RECRUITINGSafety and reactogenicity of Full-strength and Half-strength TSCV
The proportion of participants in each product group and within each age group who develop adverse events (AEs) in the first 30 minutes after parenteral immunization
Time frame: first 30 minutes after parenteral immunization
Safety and reactogenicity of Full-strength and Half-strength TSCV
The proportion of participants in each product group and within each age group who develop adverse events (AEs) in the 7 days post-vaccination.
Time frame: over 7 days post-vaccination.
Safety and reactogenicity of Full-strength and Half-strength TSCV
The proportion of participants who experience AEs through Day 29 of follow-up post-vaccination.
Time frame: through Day 29 of follow-up post-vaccination
Safety and reactogenicity of Full-strength and Half-strength TSCV
The proportion of participants who experience Serious Adverse Events through their participation in the study.
Time frame: Through Day 366 of follow-up post vaccination
Non-inferiority analysis: immunogenicity of Full-strength vs. Half-strength TSCV
Serum IgG anti-COPS antibodies (to both S. Enteritidis and S. Typhimurium antigens)
Time frame: Through day 29 post vaccination
Non-inferiority analysis: immunogenicity of Full-strength vs. Half-strength TSCV
Serum IgG anti-Vi antibodies
Time frame: Through day 29 post vaccination
Safety and reactogenicity after primary dose of TSCV and after booster dose of TSCV or Typbar-TCV™ [At each booster age group (9, 12, or 15-17 mo. of age)]
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Placebo
The proportion of participants in each product group who develop adverse events (AEs) in 7 days post-vaccination.
Time frame: over 7 days post-vaccination.
Safety and reactogenicity after primary dose of TSCV and after booster dose of TSCV or Typbar-TCV™ [At each booster age group (9, 12, or 15-17 mo. of age)]
The proportion of participants who experience AEs through Day 29 of follow-up after each vaccination.
Time frame: through Day 29 of follow-up after each vaccination.
Safety and reactogenicity after primary dose of TSCV and after booster dose of TSCV or Typbar-TCV™ [At each booster age group (9, 12, or 15-17 mo. of age)]
The proportion of participants who experience Serious Adverse Events through their participation in the study.
Time frame: Until the end of the participant study period - 6 months to 1 year post vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The rates of seroconversion of serum IgG anti-COPS at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The geometric mean titers of serum IgG anti-COPS at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The increases in geometric mean-fold titers from day 1 to 29 of serum IgG anti-COPS at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The rates of persisting seroconversion (titers remaining \> 4-fold above Day 1) of serum IgG anti-COPS at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The rates of seroconversion of serum IgG anti-Vi at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The geometric mean titers of serum IgG anti-Vi at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The increases in geometric mean-fold titers from day 1 to 29 of serum IgG anti-Vi at each booster age group
Time frame: At day 29 post booster vaccination
Immunogenicity of two-dose regimen of TSCV [At each booster age group (9, 12 or 15-17 months of age)]
The rates of persisting seroconversion (titers remaining \> 4-fold above Day 1) of serum IgG anti-Vi at each booster age group
Time frame: At day 29 post booster vaccination