Study design
The study was a single centre, randomised, double
blind doseresponse study using four doses (5, 10, 20,
and 40 ìg) of the vaccine. Subjects were allocated ran
domly to receive in a double blind manner one of the
four antigen doses. The same antigen dose of vaccine
was given on two occasions intramuscularly into the
deltoid two months apart. The primary objectives were
to assess the immunogenicity and reactogenicity of the
four doses of the vaccine and the kinetics of the
immune response. A secondary objective was to evalu
ate the hepatitis B surface antibody response to vacci
nation. Nonseroconversion was defined as the
presence of < 10 IU/l hepatitis B surface antibody.