The hepatitis B vaccine is made from a part of the virus. This is usually synthesized in the laboratory in the test tube, but other parts of the world still manufacture the vaccine from human blood. In the United States, this vaccine is uniformly produced artificially, so there is no possibility of contamination from live virus or other germs. In either case, because the vaccine contains only a part of the actual virus, the vaccine itself cannot cause hepatitis B.

A small amount of aluminum is added to the hepatitis B vaccine because the virus alone does not trigger enough of an immune response to the vaccine. The added aluminum boosts the immune system's reaction to the vaccine, allowing the vaccine to work better. If you are concerned about the presence of aluminum in vaccines, please refer to Chapter 4.