Hepatitis B is a liver infection caused by the hepatitis B virus. Some people with hepatitis B are sick for only a few weeks (known as “acute” infection), but for others, the disease progresses to a serious, lifelong illness known as chronic hepatitis B.

What is acute (short-term) hepatitis B?

Acute hepatitis B is a short-term illness that occurs within the first 6 months after someone is exposed to the hepatitis B virus. Some people with acute hepatitis B have no symptoms at all or only mild illness. For others, acute hepatitis B causes a more severe illness that requires hospitalization.

What is chronic (long-term) hepatitis B?

Some people, especially those who get infected in adulthood, are able to clear the virus from their bodies without treatment. For other people, acute hepatitis B leads to life-long infection known as chronic hepatitis B. Over time, chronic hepatitis B can cause serious health problems, including liver damage, cirrhosis, liver cancer, and even death.

How is hepatitis B spread?

Hepatitis B is spread when blood, semen, or other body fluid infected with the hepatitis B virus enters the body of someone who is not infected or has not been vaccinated. People can become infected with the virus from:

• Birth (spread from a mother who has hepatitis B to her baby during birth)
• Sex with a partner who has hepatitis B
• Sharing needles, syringes, or drug preparation equipment
• Sharing items such as toothbrushes, razors, or medical equipment (like a glucose monitor) with a person who has hepatitis B
• Direct contact with the blood or open sores of a person who has hepatitis B
• Exposure to the blood from a person who has hepatitis B through needlesticks or other sharp instruments

Who is at risk for hepatitis B?

Although anyone can get hepatitis B, these people are at greater risk:

• Infants born to mothers with hepatitis B
• People who inject drugs or share needles, syringes, and other types of drug equipment
• Sex partners of people with hepatitis B
• Men who have sex with men
• People who live with someone who has hepatitis B
• Health care and public safety workers exposed to blood on the job
• People on dialysis