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The best way to prevent hepatitis B is by getting the hepatitis B vaccine. The hepatitis B vaccine is safe and effective and is usually given as 3-4 shots over a six month period.
Hepatitis B vaccination is recommended for:
Hepatitis B is a very safe vaccine. Most people do not have any problems with it but a vaccine, like any medicine, could cause a serious reaction. Learn more about possible side effects of hepatitis B vaccine.
All children should get their first dose of hepatitis B vaccine at birth and complete the vaccine series by 6-18 months old. Hepatitis B vaccine is recommended for all babies so that they will be protected from a serious but preventable disease. Babies and young children are at much greater risk for developing a chronic infection if infected, but the vaccine can prevent this.
All children and adolescents younger than 19 years old who have not yet gotten the vaccine should also be vaccinated. "Catch-up" vaccination is recommended for children and adolescents who were never vaccinated or who did not get the entire vaccine series. Learn more about catching up on vaccines in the Who and When section.
Any adult who is at risk for hepatitis B virus infection or who wants to be vaccinated should talk to a health professional about getting the vaccine series.
Last reviewed: April 2015
Hepatitis B is a contagious liver disease that ranges in severity from a mild illness lasting a few weeks to a serious, lifelong illness. It results from infection with the hepatitis B virus. Hepatitis B can be either “acute” or “chronic.”
“Acute” hepatitis B virus infection is a short-term illness that occurs within the first six months after someone is exposed to the hepatitis B virus. Acute infection can—but does not always—lead to chronic infection.
“Chronic” hepatitis B virus infection is a long-term illness that occurs when the hepatitis B virus remains in a person’s body.
“Hepatitis” means inflammation of the liver. Toxins, certain drugs, some diseases, heavy alcohol use, and bacterial and viral infections can all cause hepatitis. Hepatitis is also the name of a family of viral infections that affect the liver; the most common types are hepatitis A, hepatitis B, and hepatitis C.
Hepatitis A, hepatitis B, and hepatitis C are diseases caused by three different viruses. Although each can cause similar symptoms, they have different modes of transmission and can affect the liver differently. Hepatitis B and hepatitis C can also begin as acute infections, but in some people, the virus remains in the body, resulting in chronic disease and long-term liver problems.
Hepatitis B is not spread by sharing eating utensils, breastfeeding, hugging, kissing, holding hands, coughing, or sneezing. Hepatitis B is not spread routinely through food or water.
However, there have been instances in which hepatitis B has been spread to babies when they have received food pre-chewed by an infected person.
Hepatitis B is spread when blood, semen, or other body fluid infected with the hepatitis B virus enters the body of a person who is not infected. People can become infected with the virus during activities such as:
Many people with chronic hepatitis B virus infection do not know they are infected since they do not feel or look sick. However, they still can spread the virus to others and are at risk of serious health problems themselves.
Although a majority of adults develop symptoms from acute hepatitis B virus infection, many young children do not. Adults and children over the age of 5 years are more likely to have symptoms. Seventy percent of adults will develop symptoms from the infection.
Symptoms of acute Hepatitis B, if they appear, can include:
On average, symptoms appear 90 days (or 3 months) after exposure, but they can appear any time between 6 weeks and 6 months after exposure.
Although anyone can get hepatitis B, in the United States, certain groups of people are at higher risk, such as those who:
The younger a person is when infected with hepatitis B virus, the greater his or her chance of developing chronic hepatitis B. Approximately 90% of infected infants will develop chronic infection. The risk goes down as a child gets older. Approximately 25–50% of children infected between the ages of one and five years will develop chronic hepatitis. The risk drops to 6–10% when a person is infected over five years of age. Worldwide, most people with chronic hepatitis B were infected at birth or during early childhood.
Microscopic view of hepatitis B.