Hepatitis B is a viral infection affecting the liver and is spread by contact with blood, semen or other bodily fluids. According to the Centers for Disease Control and Prevention (CDC), an estimated 800,000 to 1.4 million people in the United States are living with chronic hepatitis B infection. Disease severity ranges from a mild illness lasting a couple of weeks to a chronic long-term illness resulting in liver disease or even liver cancer. A highly effective vaccine protects from infection.
Hepatitis B Surface Antigen
There are two common vaccines for hepatitis B that are widely available. These vaccines are Engerix-B and Recombivax HB, and are made by the pharmaceutical companies GlaxoSmithKline and Merck, respectively. According to information from both GlaxoSmithKline and Merck, the active component (the ingredient of the injected solution that causes immunity to the hepatitis B virus) of the vaccines is a protein called "Hepatitis B Surface Antigen", which refers to a protein on the surface of the virus that is known to generate a good immune response. The body builds up an immune response specifically against this protein and the cells of the immune system recognize Hepatitis B Surface Antigen if they come in contact with it again. Should the body be exposed to the virus after vaccination, the immune system quickly recognizes the protein, kills the virus and prevents infection. In both of these vaccines, according to Merck and GlaxoSmithKline, hepatitis B surface antigen is grown in yeast and then purified and combined with the other ingredients that comprise the whole vaccine.
Aluminum Hydroxide
Inactive ingredients are components of vaccines that do not directly cause immunity, but generally serve as a filler, preservative, or other some other role. One inactive ingredient of these two (and many other) vaccines is aluminum hydroxide. This chemical is used as an "adjuvant" meaning it helps to boost the immune response. The stronger the immune response to the vaccine, the better the protection when exposed to the infectious hepatitis B virus. Thus, aluminum hydroxide serves a vital purpose of the vaccine by indirectly promoting strong immunity to the virus.
Phosphate Buffer
In both vaccines, Hepatitis B Surface Antigen and aluminum hydroxide are mixed with a type of liquid called a phosphate buffer. This liquid is at a pH similar to the blood and helps the blood resist changes in pH.
