Immunogenicity and Tolerability of Booster Typhoid Conjugate Vaccine (TCV) 5-6 Years After Initial Dose in Children in Burkina Faso

Kathleen Neuzil

Status and phase: Completed; Phase 2

Conditions: Typhoid

Treatments: Biological: Vi capsular polysaccharide-CRM197 conjugate vaccine (Vi-CRM), 0.5 mL IM

Study type: Interventional

Funder types: Other

Identifiers

NCT07624175

HP-00110239

INV 030857 (Other Grant/Funding Number)

Details and patient eligibility

About

This study evaluated the persistence of immunity following primary typhoid conjugate vaccination in early childhood and assessed the immunogenicity and safety of a booster dose administered 5-6 years later. Children previously enrolled in a Phase 2 randomized clinical trial of Vi-tetanus toxoid conjugate vaccine (Vi-TT) were re-enrolled at 6-7 years of age. Participants who previously received Vi-TT received a booster dose of Vi-CRM, while control participants received their first TCV dose.

Anti-Vi IgG antibody responses were measured at baseline and 28 days post-vaccination. Safety was assessed through solicited and unsolicited adverse events. This study provides data on durability of TCV immunity and the potential role of booster dosing in endemic settings.

Full description

This prospective, open-label interventional study followed children previously enrolled in a Phase 2 randomized controlled trial of Vi-TT administered in infancy. Approximately 5-6 years later, participants were re-contacted and assigned to receive either a booster TCV dose (Vi-CRM) or a first TCV dose depending on prior vaccination status.

Immunogenicity was assessed using anti-Vi IgG ELISA assays at baseline and 28 days post-vaccination. Safety outcomes included solicited and unsolicited adverse events and serious adverse events. The study was conducted at a single clinical site in Ouagadougou, Burkina Faso.

Enrollment: 147 patients

Sex: All

Ages: 6 to 7 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Male or female children previously enrolled in the 2018-2019 Phase 2 typhoid conjugate vaccine trial
• Residence within study area
• Parent/guardian provides informed consent

Exclusion criteria

• Receipt of blood products within 6 months
• Prior typhoid conjugate vaccine receipt outside the study
• Medical condition interfering with evaluation
• Acute illness or fever prior to vaccination (temporary exclusion)

Trial design

Primary purpose: Prevention

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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147 participants in 1 patient group

typhoid conjugate vaccine (TCV)

Experimental group

Description:

Received one intramuscular dose of Vi-CRM (TYPHIBEV®)

Treatment:

Biological: Vi capsular polysaccharide-CRM197 conjugate vaccine (Vi-CRM), 0.5 mL IM