Hepatitis B is an infection of the liver caused by the hepatitis B virus (HBV). Hepatitis B is one of the major contagious diseases against which children and adults in this country are not generally protected. While many people recover from hepatitis B without ever having any symptoms, others may have jaundice (yellow-colored skin), joint pains, persistent arthritis, or chronic liver disease, sometimes leading to liver failure and cirrhosis, or to cancer of the liver in later life.

The hepatitis B virus may be obtained at birth, through contact with blood from an infected person, or through sexual contact, with a hepatitis B carrier. The virus may enter through minor scratches or cuts in the skin, or through intact mucous membranes in the mouth or elsewhere. It may be obtained from fresh blood or from blood-contaminated objects which may have been dry for as long as a month. Because of these possibilities, people can get hepatitis B at work, school, or day care, as well as at birth or through sexual contact or accident.

There are more than a million hepatitis B carriers in the United States, and nearly 5,000 people die each year from liver disease due to hepatitis B infection. (Carriers have the virus and are able to pass it to others, but do not appear sick.) At least 300,000 children and adults in the U.S. become infected with hepatitis B virus each year. Up to 90% of infants, and from 25 to 50% of children under the age of 5, will become chronic hepatitis B carriers if they are infected. The risk of hepatitis B infection increases greatly during adolescence, though the full impact of adolescent infections is not recognized until years later when chronic lever disease and liver cancer may develop.

Hepatitis B vaccine has been used in this country since 1982, but its use prior to 1992 has been recommended only for medical personnel and those at high risk of acquiring the disease in other ways, including infants born to mothers with positive hepatitis B blood tests, and intravenous drug users.

Because this plan has not resulted in control of hepatitis B in this country, both the U.S. Public Health Service and the American Academy of Pediatrics now recommend that hepatitis B vaccine be given to all infants and to all adolescents known to be at risk through work or sexual activity.

Hepatitis B vaccine protects more than 95% of infants who have received it according to the recommended schedule. Side effects of the vaccine are minor, consisting of soreness at the injection site in 3%-29% of those receiving the vaccine. A fever greater than 100 degrees F has been reported in 1-6% of children and adults receiving the vaccine. Hypersensitivity to yeast in the vaccine has been reported rarely, but no serious adverse effects of any kind have yet been definitely linked to hepatitis B vaccine given to children.

The recommended 3 doses of vaccine are given to infants at birth or soon thereafter, one to two months later, and at 6 to 18 months of age or 4 months after the second dose. The three doses for adolescents and older children are given at similar intervals.