ORAL TYPHOID VACCINE

Contains the attentuated strain Ty21a of S.typhi. The attenuation of the virulence of this strain is due to the absence of the enzyme Uridine diphosphate galactose-4 epimerase which is essential for the production of the lipopolysaccharide'O'antigen.The absence of this enzyme makes Ty21a avirulent but highly immunogenic. This oral vaccine acts in a way similar to the typhoid bacillus itself, but instead of causing typhoid fever, it gives immunity against it.

Indications

Prophylactic immunisation oildren over 6 years against typhoid fever.

Dosage

One capsule on days 1,3 and 5 irrespective of age. It is to be taken 1 hour before a meal with cold or lukewarm milk or water.

Contra-Indications

Acute febrile illness, acute intestinal infection, congenital or acquired immuno-deficiency

Special Precautions

Sulphonamides known to be active against S.typhi should not be given concomitantly.

Side Effects

Fever & mild gastro-intestinal effects.

Drug Interactions

Failure of vaccination with high dose systemic corticosteroid therapy, immunosuppressive therapy and irradiation.