Signs and symptoms of hepatitis B range from mild to severe. They usually appear about one to four months after you've been infected, although you could see them as early as two weeks post-infection. Some people, usually young children, may not have any symptoms.

Hepatitis B signs and symptoms may include:

• Abdominal pain
• Dark urine
• Fever
• Joint pain
• Loss of appetite
• Nausea and vomiting
• Weakness and fatigue
• Yellowing of your skin and the whites of your eyes (jaundice)

Hepatitis B infection is caused by the hepatitis B virus (HBV). The virus is passed from person to person through blood, semen or other body fluids. It does not spread by sneezing or coughing.

Common ways that HBV can spread are:

• Sexual contact. You may get hepatitis B if you have unprotected sex with someone who is infected. The virus can pass to you if the person's blood, saliva, semen or vaginal secretions enter your body.
• Sharing of needles. HBV easily spreads through needles and syringes contaminated with infected blood. Sharing IV drug paraphernalia puts you at high risk of hepatitis B.
• Accidental needle sticks. Hepatitis B is a concern for health care workers and anyone else who comes in contact with human blood.
• Mother to child. Pregnant women infected with HBV can pass the virus to their babies during childbirth. However, the newborn can be vaccinated to avoid getting infected in almost all cases. Talk to your doctor about being tested for hepatitis B if you are pregnant or want to become pregnant.

Acute vs. chronic hepatitis B

Hepatitis B infection may be either short-lived (acute) or long lasting (chronic).

• Acute hepatitis B infection lasts less than six months. Your immune system likely can clear acute hepatitis B from your body, and you should recover completely within a few months. Most people who get hepatitis B as adults have an acute infection, but it can lead to chronic infection.
• Chronic hepatitis B infection lasts six months or longer. It lingers because your immune system can't fight off the infection. Chronic hepatitis B infection may last a lifetime, possibly leading to serious illnesses such as cirrhosis and liver cancer.

The younger you are when you get hepatitis B — particularly newborns or children younger than 5 — the higher your risk of the infection becoming chronic. Chronic infection may go undetected for decades until a person becomes seriously ill from liver disease.

Hepatitis B spreads through contact with blood, semen or other body fluids from an infected person. Your risk of hepatitis B infection increases if you:

• Have unprotected sex with multiple sex partners or with someone who's infected with HBV
• Share needles during IV drug use
• Are a man who has sex with other men
• Live with someone who has a chronic HBV infection
• Are an infant born to an infected mother
• Have a job that exposes you to human blood
• Travel to regions with high infection rates of HBV, such as Asia, the Pacific Islands, Africa and Eastern Europe

Having a chronic HBV infection can lead to serious complications, such as:

• Scarring of the liver (cirrhosis). The inflammation associated with a hepatitis B infection can lead to extensive liver scarring (cirrhosis), which may impair the liver's ability to function.
• Liver cancer. People with chronic hepatitis B infection have an increased risk of liver cancer.
• Liver failure. Acute liver failure is a condition in which the vital functions of the liver shut down. When that occurs, a liver transplant is necessary to sustain life.
• Other conditions. People with chronic hepatitis B may develop kidney disease or inflammation of blood vessels.