Two batches of a new hepatitis A/hepatitis B combined vaccine were tested in 242 healthy students. Three injections, given at 0, 1 and 6 months, produced seroconversion rates and hepatitis A virus (HAV) and hepatitis B surface antigen (HBsAg) antibody levels comparable to those reported after administration of separate monocomponent vaccines. The vaccine proved to be safe and well-tolerated. Influence of host factors, such as elevated body mass index or gender, were investigated and proven to be of little influence on the immunoresponse.