Phase II multicentre double-blind randomised controlled trial of a Bivalent VaccInation against Salmonella Typhi and Paratyphi A (BiVISTA) using a controlled human infection model of paratyphoid A infection: study protocol.

ABSTRACT:

Introduction

Enteric fever, primarily caused by Salmonella enterica Typhi and Salmonella enterica Paratyphi A (SPA), is endemic mainly in South Asia, disproportionately affecting school-age children. Although typhoid conjugate vaccines (TCVs) are effective and implemented in many countries, no licensed vaccine exists against paratyphoid A. Bivalent vaccines targeting both S. Typhi and SPA may address this gap. Although field efficacy trials are not considered feasible, controlled human infection models (CHIMs) offer an alternative pathway for evaluating vaccine efficacy. This will be the first efficacy study of a bivalent vaccine against typhoid and paratyphoid A using a paratyphoid CHIM.

Methods and analysis

This is a phase II multicentre, double-blind, random

SUBMITTER: Paganotti Vicentine M 

PROVIDER: S-EPMC12853460 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature