ABSTRACT
The immunogenicity of both Typhoid Vi polysaccharide and inactivated Hepatitis A vaccines were tested and the immunogenic reflection of each vaccine on the other one in combination was detected. Groups of balb/C mice were immunized with different formulations containing different concentrations of typhoid Vi polysaccharide and hepatitis A vaccines, Four experiments were done a fellows:-Exp. I group I [mice was injected with alum 1mg/ ml], group 2, 3, 4 were immunized with three concentration [25, 12.5.6.25 micro g / ml typhoid [Ty] vaccine respectively. Exp. II groups 5, 6, 7 were immunized with hepatitis A [HA] vaccine with three concentration [400, 200, 100 IU/ ml respectively. Exp. III group 3A was immunized with [25 micro g / ml Ty vaccine], groups 33, 3C, 3D were immunized with combination of typhoid and hepatitis A vaccines [25 micro g / ml Ty +400, 200, 100 IU /ml HA respectively]. Exp. IV group 4A was immunized with [400 IU /ml HA vaccine], groups 43, 4C were immunized with combination of hepatitis A and typhoid vaccines. The results revealed that hepatitis A vaccine has a synergistic effect on the immunogenicity of typhoid Vi vaccine. On the other hand, the immune response against hepatitis A was higher when combined with different concentrations of typhoid vaccine