TYVEGHA
A cluster-randomised controlled Phase IV trial assessing the impact of a VI-Polysaccharide conjugate vaccine in preventing typhoid infection in Asante Akim, Ghana (TyVEGHA)
Background
Typhoid fever remains a significant public health concern in Sub-Saharan Africa, with incidence rates exceeding 100 cases per 100,000 person-years. In Ghana, the disease is prevalent and displays spatiotemporal variations, affecting rural and semi-urban communities the most. Caused by Salmonella enterica, typhoid is transmitted through contaminated food or water.
While antimicrobial treatment has been the mainstay therapy, the rise of drug resistance, particularly to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole during large Asian outbreaks in the 1980s and 1990s has heightened the need for preventive measures such as vaccination. The World Health Organization now recommends the use of typhoid conjugate vaccines (TCVs) in endemic countries, with Gavi, the Vaccine Alliance, providing subsidized access to these vaccines.
Study Overview and Objectives
The Typhoid Vaccine Ghana (TyVEGHA) study is a Phase IV controlled trial evaluating the effectiveness of the Typbar® TCV in preventing typhoid infection among children in Asante Akim, Ghana. The trial is conducted in collaboration with the International Vaccine Institute and other partners.
The study area covers a population of about 140,000, characterized by semi-urban and rural settlements with low migration rates. Fifteen villages are participating, with the main trial center located in Asante Akim Agogo. A total of 80 clusters were created based on administrative and community boundaries, with cluster sizes ranging from 85 to 896 people.
Participants are randomly assigned, using a stratified block randomization method, to receive either the Vi-TT vaccine or the comparator MCV-A vaccine. The allocation process is guided by the Master Vaccine Randomization List, handled by unblinded study staff.
Funding Partners: TyVEGHA is part of broader efforts under the Typhoid Conjugate Vaccine Introduction in Africa (THECA) and it’s funded by the European and Developing Countries Clinical Trials Partnership (EDCTP) alongside International Vaccine Institute (IVI)
