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Hepatitis B Vaccine and Why You Need It


Updated April 16, 2014

Hepatitis B is a viral infection that affects the liver and can have serious consequences of liver failure, cirrhosis (hardening of the liver) and hepatocellular cancer (liver cancer). The hepatitis B virus infects about 400 million people worldwide with about 1.5 million living in the United States. The virus is spread from person to person through direct contact with infected blood and semen. The most common routes of infection include Mother to baby, IV drug use via shared needles, needle stick injuries and having sex with someone who has hepatitis B.

The best way to protect yourself from hepatitis B is to get the hepatitis B vaccine. There are two vaccines available in the United States that protect against hepatitis B: Recombivax HB and Engerix-B. There are also combination vaccines that protect against two viruses. Twinrix, for example, protects against hepatitis B and hepatitis A.

Who Needs the Hepatitis B Vaccine?

Anyone who wants to be protected against hepatitis B should be vaccinated. Some people, however, have a higher chance of exposure to the virus because of their lifestyle or the nature of their work. These people should strongly consider getting the hepatitis B vaccine.

The HBV vaccine is now part of the regular immunization schedule and recommended for all babies. While babies probably won't come in to contact with infected blood, older children and teenagers may. Children infected with HBV may be asymptomatic. Because of this, immunizing a baby against hepatitis B can provide decades of protection, keeping the child safer from exposure in to young adulthood.

Is the Hepatitis B Vaccine Safe?

Yes. Hepatitis B vaccines have few, if any, side effects. The most common complaint is a little pain around the area of the injection, which is a fair trade off considering the serious complications often possible with an actual hepatitis B infection. Since the hepatitis B vaccines were approved in the 1980s, they have had significant time to be studied and proven.

Hepatitis B vaccines are thimerosal-free and do not contain live viruses. This means that there is no danger of getting toxic mercury or hepatitis B infection from the vaccine itself.

How Does the Hepatitis B Vaccine Work?

Hepatitis B vaccines simulate an infection in your body by introducing a protein called "HBsAG," or hepatitis B surface antigen. The protein is produced by inserting selected genetic material from a hepatitis B virus and "growing" it in a yeast cell. This produces purified HBsAG that can't cause a real infection, but can still cause an immune response from your body. Hepatitis B vaccines work by simulating an infection in your body. The virus will have very little success getting to where it can start replicating (the hepatocytes), and you shouldn't get hepatitis B. According to hepatitis B vaccine studies, an immunized person should have a protection level between 90% and 95% for 15 years or more.

How Is the Vaccine Given?

The hepatitis B vaccine requires 3 or 4 shots over 6 months. The injection is given in a muscle, usually the arm for adults or the thigh for infants and children.

What Is HBIG?

Sometimes a doctor may recommend HBIG, hepatitis B immune globulin. Immune globulin is a type of immunization therapy that uses antibodies instead of viruses. This type of immunity is called "passive immunity," because it offers protection without your body having to do anything. HBIG provides only short-term protection and is only used in special circumstances. For the best protection, hepatitis B vaccine is the most efficient and effective method. For more information about immune globulin, read "What Is Immune Globulin?".


Centers for Disease Control and Prevention. June 23, 2008. Hepatitis B.

Pickering, LK (ed), The Red Book: Report of the Committee on Infectious Diseases, 26th e. American Academy of Pediatrics, 2003. 318-336.

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