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Project Topic
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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 mass-vaccination 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. The objectives of THECA are to: • Conduct a Typbar-TCV® Phase 3 cluster-randomized trial to measure population-level vaccine protection (Ghana); • Conduct a Typbar-TCV® mass-vaccination campaign with a nested case-control study to measure vaccine protection under realistic public health conditions (DRC); • Generate data on mass-campaign feasibility, cost-effectiveness, safety, immunogenicity and impact on antimicrobial resistance; • Enhance African clinical trials capacity; and • Support regulatory affairs for TCV introduction in African early-adopter countries (Ghana, DRC, Madagascar, Burkina-Faso) These targeted objectives will yield data critical to public health decision-making on TCV introductions in Africa where a vast majority of Gavi-eligible countries are represented. Consortium members’ awarded co-funding for aligned activities include UM efficacy studies (BMGF, €17.3.M) and the International Vaccine Institute multi-country typhoid surveillance program (BMGF, €2.0M) and impact assessment work (WP5) for this project (BMGF, €2.7M). Existing typhoid surveillance activities in Ghana and the DRC provide an excellent platform for clinical trials and will be leveraged to accomplish THECA objectives. THECA will fill a large gap in ongoing large-scale typhoid control efforts and will yield critical data to enable African and international policymakers to make informed decisions on TCV introductions.
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