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The morbidity and mortality of typhoid fever caused by Salmonella enterica serovar Typhi (S. Typhi) and the emergence of drug-resistant S. Typhi infections are straining health resources in certain regions. Existing vaccines have poor acceptability or immunogenicity in children. A vaccine based on S. Typhi Vi polysaccharide conjugated to tetanus-toxoid carrier (Typbar-TCV, or TCV) was found to be safe and immunogenic in children in endemic regions. TCV had 54.6% protective efficacy against S. Typhi in a controlled human infection model in a nonendemic area. (TCV is licensed in India and Nepal.) To test efficacy in an endemic area, investigators in Nepal randomized 20,019 children aged 9 months to 16 years in a 1:1 ratio to receive one dose …