The aim of the Typhoid Conjugate Vaccine Introduction in Africa program (THECA) is to generate evidence critical to rational decision-making on the introduction of Typhoid Conjugate Vaccine (TCV) into routine immunization programs in typhoid-endemic countries in Africa. THECA will conduct two large-scale TCV studies – a cluster-randomised trial in Agogo, Ghana and a mass vaccination campaign in Kisantu, Democratic Republic of Congo. In addition to measuring vaccine effectiveness, these studies will generate important information about the feasibility and cost-effectiveness of different vaccine introduction approaches. Consortium members are working with potential early introducer countries in Africa to help gather supportive evidence to apply for TCV introduction support from Gavi, the Vaccine Alliance (Gavi).
The THECA consortium, coordinated by the University of Cambridge, brings together a diverse range of partners, including Kwame Nkrumah University of Science and Technology (Ghana), University of Antananarivo (Madagascar), University of Ouagadougou (Burkina Faso), Institut National de Recherche Biomédicale (Democratic Republic of the Congo), International Vaccine Institute (Republic of Korea), Foundation Mérieux (France), Institute of Tropical Medicine Antwerp (Belgium), International Centre for Diarrhoeal Disease Research, Bangladesh (Bangladesh), and the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine (USA). These member organizations have a proven record of accomplishment in conducting surveillance and vaccine trials. Funding for THECA comes from the European and Developing Countries Clinical Trials Partnerships (EDCTP) and the Bill & Melinda Gates Foundation.
THECA is working closely with the Typhoid Vaccine Acceleration Consortium (TyVAC), a partnership between the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, the Oxford Vaccine Group at the University of Oxford, and PATH, an international non-profit. TyVAC aims to accelerate the introduction of new TCV as part of an integrated approach to reducing the burden of morbidity and mortality from typhoid in countries eligible for support from Gavi.
TyVAC is conducting studies in Malawi, Nepal, Bangladesh and Burkina Faso. THECA aims to provide additional supportive data on vaccine performance from African settings to support decision-making around TCV introduction. Given that the majority of Gavi-eligible countries are in Africa, it is important to provide additional data on the effectiveness, feasibility, and cost-effectiveness of TCVs in African settings.
The objectives of THECA are:
- Measure population-level vaccine protection of Typbar-TCV® in a Phase 3 Cluster Randomized Trial (CRT, Ghana);
- Evaluate effectiveness of Typbar-TCV© through a mass vaccination campaign in the Democratic Republic of Congo (DRC);
- Generate data on mass-campaign feasibility, cost-effectiveness, safety, immunogenicity and impact on antimicrobial resistance;
- Enhance clinical trial capacity in Africa; and
- Support regulatory affairs for TCV-introduction in African early-adopter countries (Madagascar, Burkina Faso, Ghana, DRC)
These activities are designed to fill existing data gaps and support accelerated introduction of TCV in endemic countries. The CRT will provide the first estimate of herd protection conferred by TCV in an African setting. The mass vaccination study in the DRC will provide data on vaccine effectiveness, safety, feasibility, and cost-effectiveness of TCV when deployed through a large-scale campaign. These data will help decision-makers to understand the full public health value of national TCV programs.