The first experimental study on a candidate combined vaccine against hepatitis A and hepatitis E.

To test the possibility of developing a combined vaccine against hepatitis A and E, groups of mice were immunized with different formulations containing different dosages of a commercially inactivated hepatitis A vaccine and a candidate recombinant hepatitis E vaccine. Monovalent vaccine components were used as controls. The experimental results showed that the combined vaccine could induce neutralizing antibodies against both hepatitis A virus (HAV) and hepatitis E virus (HEV) effectively in mice. Moreover, the inactivated hepatitis A vaccine could increase the immunogenicity of the recombinant HEV protein, and the recombinant HEV protein had no adverse effects on the immunogenicity of the inactivated HAV vaccine. Thus, the present study demonstrates an important first step for the further development of a combined hepatitis A and E vaccine.