Overview of the Typhoid Conjugate Vaccine Pipeline: Current Status and Future Plans.

Typhoid fever remains a common and serious disease in populations that live in low- and middle-income countries. Treatment usually consists of antibiotics, but problems with drug-resistant strains have been increasing in endemic countries, making treatment prolonged and costly. Improved sanitation and food hygiene have been effective in controlling the disease in the industrialized world, but these steps are associated with socioeconomic progress that has been slow in most of the affected areas. Therefore, vaccination is an effective way to prevent the disease for the short to medium term. Oral typhoid vaccine and Vi polysaccharide typhoid vaccine (Vi polysaccharide) have been available for many years, yet a large population, in particular infants and children aged <2 years, remains at higher risk. Recently, with the availability of Vi polysaccharide-based conjugate vaccines and funding to support vaccination from the Gavi alliance, there is great momentum for typhoid prevention efforts. Supply of the vaccine will be critical, and there are multiple efforts to make new typhoid vaccines accessible and available to populations that desperately need them.