Immunogenicity and reactogenicity of a booster dose of a typhoid conjugate vaccine (TCV) in Malawian pre-school children.

ABSTRACT:

Background

We assessed persistence of typhoid immunity conferred by Vi polysaccharide-tetanus toxoid (Vi-TT) conjugate vaccine (TCV) four years post-vaccination and immunogenicity of a booster dose of Vi-TT given at age five.

Methods

In 2018, a phase 3 trial of Vi-TT in Malawi randomised children 1:1 to receive Vi-TT or meningococcal capsular group A conjugate vaccine (control). Subsequently, TCV was licensed and recommended in the region. In 2023, children vaccinated at 9-11 months in the original trial received a second (Booster- TCV) or first (1st-TCV) Vi-TT dose, at age five. Serum collected at days 0, 28, and 160-180 days after vaccination was tested for anti-Vi immunoglobulin (Ig)G and IgA, reported as enzyme-linked immunosorbent assay units (EU)/mL. Seroconversion was

SUBMITTER: Nampota-Nkomba N 

PROVIDER: S-EPMC11872497 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature