Immunogenicity of a yeast-derived hepatitis B vaccine (Engerix-B) in healthy young adults.

In a study comparing the safety and immunogenicity of a recombinant DNA yeast-derived hepatitis B vaccine with that of a plasma-derived vaccine in young female adults, 50 subjects were vaccinated with the former and 29 with the latter vaccine according to a 0, 1, and 6 month vaccination schedule. Results indicated that the yeast-derived vaccine was safe and highly immunogenic. Two months after the second vaccine dose, 86% of subjects seroconverted, a rate which increased to 100%, 30 days after the booster dose. Moreover, anti-HBs geometric mean titres increased progressively after the first two doses and rose markedly to 1098 IU/l after the booster dose. Although similar rates of seroconversion were obtained with both vaccines, the anti-HBs GMT of the plasma-derived vaccine was higher (P less than 0.05) than that elicited by the yeast-derived vaccine.