Typhoid fever is very serious infection as sometimes it takes times to respond to oral medicine and sometime oral medicine don't work at all. In that case resistant infection has to be ruled out by admitting the child, starting Injection to overcome the resistant infection. Patients gets lots of weakness during and after infection also. By now your pediatrician must have advised for hospitalisation. Hospitalisation helps in many ways,we can avoid oral medicine,we can provide IV nutrition in the form of saline, vitamin's , Patient gets rest also. Hope it's help you.