Effect of a novel typhoid conjugate vaccine in Africa: a multicenter study in Ghana and the DRC

Recent studies have provided evidence for typhoid fever (TF) as a major poverty-related public health concern and a cause of diarrhea throughout Africa and Asia. Following recommendations by the WHO Strategic Advisory Group
of Experts in Q3/2017, typhoid conjugate vaccines (TCV) are now Gavi-subsidized. To date, one candidate, Typbar-TCV® (Bharat-Biotech, India), has successfully been licensed, solely on immunogenicity data, in several countries.
WHO-prequalification was awarded in Q4/2017. For successful TCV introductions into Gavi-eligible countries,additional data are needed, including data on long-term safety, immunogenicity, vaccine clinical efficacy, effectiveness, including population-level protection (direct and herd), and cost-effectiveness. To help provide this evidence-base, the Gates Foundation (BMGF) award granted to the University of Maryland (UM) includes three Typbar-TCV® efficacy studies – a cluster-randomized trial (CRT) in Bangladesh and two individual-randomized trials (Malawi, Nepal). We propose to complement the work with an additional Typbar-TCV® CRT in Ghana to provide estimates of population-level vaccine protection supplementing the Malawian efficacy data. Additionally, we propose a massvaccination campaign with a nested case-control study in the Democratic Republic of Congo (DRC) to measure real-life vaccine effectiveness in Africa and generate data on feasibility, long-term protection, and safety.

Recent studies have provided evidence for typhoid fever (TF) as a major poverty-related public health concern and a cause of diarrhea throughout Africa and Asia. Following recommendations by the WHO Strategic Advisory Group
of Experts in Q3/2017, typhoid conjugate vaccines (TCV) are now Gavi-subsidized. To date, one candidate, Typbar-TCV® (Bharat-Biotech, India), has successfully been licensed, solely on immunogenicity data, in several countries.
WHO-prequalification was awarded in Q4/2017. For successful TCV introductions into Gavi-eligible countries,additional data are needed, including data on long-term safety, immunogenicity, vaccine clinical efficacy, effectiveness, including population-level protection (direct and herd), and cost-effectiveness. To help provide this evidence-base, the Gates Foundation (BMGF) award granted to the University of Maryland (UM) includes three Typbar-TCV® efficacy studies – a cluster-randomized trial (CRT) in Bangladesh and two individual-randomized trials (Malawi, Nepal). We propose to complement the work with an additional Typbar-TCV® CRT in Ghana to provide estimates of population-level vaccine protection supplementing the Malawian efficacy data. Additionally, we propose a massvaccination campaign with a nested case-control study in the Democratic Republic of Congo (DRC) to measure real-life vaccine effectiveness in Africa and generate data on feasibility, long-term protection, and safety.