Abstract
The first vaccine against human hepatitis B virus was licensed for use in the United States in 1981 and became commercially available in 1982.1 The development of this vaccine represented a milestone in medicine and was the product of two decades of intensive research into the structure and biology of hepatitis B virus. The first vaccine consisted of particles of purified and inactivated hepatitis B surface antigen (HBsAg) extracted from pooled plasma from long-term carriers of HBsAg. A second milestone was reached in 1984 with the development of a recombinant hepatitis B vaccine, the first human vaccine produced with molecular . . .