The development of the hepatitis B vaccine is considered to be one of the major achievements of modern medicine. The first hepatitis B vaccine was licensed in 1981. This first-generation vaccine was prepared by removing plasma from HBV carriers and concentrating out a surface antigen (the S antigen). Derivation from plasma left concerns regarding the potential to transmit blood-borne infections, and therefore a second-generation of yeast-derived vaccines was created in the mid-1980s. These second-generation vaccines also contain the S antigen and are currently used for the universal vaccination of newborns and adults in many countries worldwide.