Bio-typh injection contains active components called as purified Vi capsular polysaccharide of Salmonella typhi (Ty 2 strain). It is a preventive measure used to protect against typhoid fever, a bacterial infection caused by Salmonella Typhi. Typhoid fever is typically contracted by consuming contaminated food or water. Vaccinated individuals are less likely to become infected with S. Typhi, which can help reduce the transmission of the bacteria within communities and prevent outbreaks. If you have a severe allergic reaction to any component of the Bio typh vaccine (e.g., a previous dose of the vaccine or any of its ingredients), you should not receive the vaccine. Vaccination may be contraindicated if you have experienced a severe allergic reaction or other serious side effects following a previous dose of a Bio typh injection. While Bio typh are generally considered safe during pregnancy, they should be used cautiously, especially during the first trimester. If you have received a blood or plasma transfusion, waiting for some time before getting the Bio typhoid vaccine is recommended. Bio typh injections are generally safe for older adults. However, the specific vaccine and its administration route may vary based on age. Consult with a healthcare provider to determine your child's appropriate vaccine typh and schedule.