Can be administered with yellow fever and hepatitis A vaccine "The Vi polysaccharide vaccine can be co-administered with other vaccines relevant for international travelers such as yellow fever and hepatitis A and with vaccines of the routine child hood immunization programs"- Park There are two anti typhoid vaccines in use: Vi polysaccharide vaccine Subunit vaccine Composed of purified Vi capsular polysaccharide from the Ty 2 S. Typhi strain Administered subcutaneously or intramuscularly Stable for 6 months at 37degC and for 2 yrs at 22degC. The recommended storage temp. is 2-8degC. Schedule: Only Single dose of vaccine is required. To maintain protection revaccination every 3 yrs is recommended. Licensed for use in individuals 2 yrs. Immunity develops 7 days after injection of vaccine. No serious adverse events and a minimum of local side effects are associated with it. No contraindications except severe hypersensitivity reaction in previous vaccine injection. It is safe for HIV positive individuals. Ty 21a vaccine Orally administered live attenuated (Ty 2 strain of S. typhi) vaccine. / * Available as enteric coated capsules. Storage at 2-8degC, retains potency for 14 days at 25degC. Licensed for use in individuals 5 yrs. 3 dose regimen - Day 1, Day 3 and Day 5 Immunity develops 7 days after last dose. This series to be repeated every 3 yrs. in endemic areas and every year for travelers from non endemic to endemic countries. May be given simultaneously with live vaccines of polio, cholera, yellow fever and MMR. Proguanil and antibacterial drugs should be stopped 3 days before and 3 days after vaccine administration as these drugs may harm live bacterial vaccines. Avoided during diarrhoea as efficacy will reduce. Can be given to HIV +ve, asymptomatic persons with CD4 cell count of > 200/mm3 Well tolerated and has low rates of adverse events. Not recommended in congenital or acquired immunodeficiency, acute febrile illness, acute intestinal infection and in patients on antimitotic drugs.