Typhoid vaccines are vaccines that prevent typhoid fever. Several types are widely available: typhoid conjugate vaccine (TCV), Ty21a (a live oral vaccine) and Vi capsular polysaccharide vaccine (ViPS) (an injectable subunit vaccine). Depending on the type, typhoid vaccines are estimated to be about 50% to 85% effective. The Vi-rEPA vaccine is efficacious in children.
The World Health Organization (WHO) recommends vaccinating all children in areas where the disease is common. Otherwise they recommend vaccinating those at high risk. Vaccination campaigns can also be used to control outbreaks of disease. Depending on the vaccine, additional doses are recommended every three to seven years. In the United States the vaccine is only recommended in those at high risk such as travelers to areas of the world where the disease is common.