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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
528
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.
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.
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.
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.
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.
Time frame: 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.
Time frame: 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.
Time frame: At Visit 3 of the current study (36 months after last vaccination in the parent studies)
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