A single typhoid vaccine trial in Malawi is now tracking how two distinct forms of Salmonella spread through communities and whether a new vaccine can stop them. This matters because typhoid and invasive non-typhoidal Salmonella (iNTS) together cause hundreds of thousands of serious illnesses and deaths each year in sub-Saharan Africa, yet no vaccine is widely available for iNTS, and the first typhoid conjugate vaccine has not been tested at scale in Africa. The research fills a critical gap: it will map where and how these bacteria move through households, water supplies, and schools, and measure who gets sick and why. If the work succeeds, it could accelerate the introduction of typhoid vaccines across the region and push iNTS vaccines into early clinical trials for the very young children most at risk. Beyond saving lives directly, the findings could reshape how governments and international agencies prioritise sanitation, water infrastructure, and vaccination programmes in urban and rural settings. The project also trains the next generation of African clinician-scientists, building long-term research capacity where it is most needed.
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I am a clinician-scientist who has worked for 21 years in Malawi towards vaccine-prevention of invasive disease caused by 2 distinct groups of Salmonellae: Typhoid fever (caused by Salmonella Typhi), causing >3M cases and 33,000 deaths annually in sub-Saharan Africa. Typhoid predominantly affects healthy school-aged children (5-18y). I am leading the first typhoid conjugate vaccine (TCV) trial in Africa, of >28,000 children. Invasive non-typhoidal Salmonella disease, also called 'iNTS disease' (caused by Salmonella Typhimurium and Salmonella Enteritidis), which causes 3.4M cases of serious illness and over 680,000 deaths annually. Two thirds of these occur in sub-Saharan Africa. iNTS disease predominantly affects very young children ( Over the next 5 years, I will make translational advances in typhoid and iNTS disease, in 3 workstreams: Workstream 1: Epidemiology: I will lead research to understand the burden and distribution of typhoid and iNTS disease, and their transmission in urban and rural populations and communities. We will achieve this by census and geospatial mapping of urban and rural areas, including sanitation and water supplies, level of poverty and schools. We will then conduct enhanced passive disease incidence surveillance for disease by blood culture and community serosurvey. We will follow-up cases, to understand typhoid and iNTS transmission in the household and broader community using Susceptible-Infected-Recovered (SIR) and geospatial models. The same platforms will be used to measure vaccine impact. Workstream 2: Host: I will lead studies on the immune responses to Salmonella infection, in order to optimise vaccines or other preventive strategies. We will study the interactions of cells, antibodies and complement to understand susceptibility and to optimise vaccine strategy. We will study the gut mucosal cellular response to understand gut colonisation, persistence and invasion, and the way in which gut exposure primes a protective systemic immune response. And we will study the gut microbiota, to describe how it influences and modulates invasion, persistence, immunity and transmission of Salmonella. Workstream 3: Vaccine: In the next 5 years we will measure TCV immunogenicity in healthy and HIV-exposed children. We will conduct cost-of-illness and cost effectiveness analyses. We will measure the impact of the vaccine in lives saved, cases of typhoid prevented, and prevention of antibiotic resistance. We will, at the same time, accelerate emerging iNTS disease vaccines into early clinical trials among very young children, using our experience, expertise and tools from typhoid vaccination. To support these workstreams, I will conduct 3 cross-cutting activities: Discussing and explaining Salmonella science and research to engage the communities with whom we work. We will also engage nationally through newspapers, radio and television Engaging, supporting and advocating with the Malawi government and other stakeholders and agencies, using our research findings, to accelerate the introduction of vaccines Training the next generation of doctors and scientists to be the researchers of the future
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