Home   >   Medicine   >   Infectious Diseases
Hepatitis B

Hepatitis B is a contagious liver disease caused by the hepatitis B virus. It can be either acute or chronic. Acute Hepatitis B virus infection is a short-term illness that occurs within the first 6 months after someone is exposed to the Hepatitis B virus. Chronic Hepatitis B is a serious disease that can result in long-term health problems, including liver damage, liver failure, liver cancer, or even death.

The CDC estimates that nearly 43,000 people contracted hepatitis B in the United States in 2007, although the number of reported cases is much lower because some people do not show symptoms. There are an estimated 800,000 to 1.4 million chronic cases in the United States. Globally, there are about 360 million chronically infected people, and as many as 626,000 people die of hepatitis B every year.


Hepatitis B virus can be found in the blood, semen, vaginal fluids, and other body fluids of infected people. Transmission happens when infected body fluids enter another person’s body. The virus is most commonly transmitted in the following ways:

  • Sex with an infected partner
  • Contact with the blood of an infected person
  • Sharing of needles, syringes, razors, or toothbrushes with an infected person
  • Maternal-infant transmission during childbirth

Hepatitis B is not transmitted through shaking hands, coughing, sneezing, breastfeeding, or sharing cups and utensils.


Hepatitis B does not always cause obvious symptoms. Children are less likely than adults to exhibit symptoms, but they are more likely than adults to develop chronic hepatitis B after an acute infection.

Symptoms of acute hepatitis B include the following:

  • Jaundice
  • Fatigue
  • Abdominal pain
  • Nausea or vomiting
  • Fever
  • Loss of appetite
  • Dark urine
  • Joint pain

Symptoms of acute hepatitis B generally appear three months after exposure to the virus and may last for a period of several weeks to six months.

People with chronic hepatitis B may exhibit no symptoms for two to three decades, but around 15 to 25 percent of those chronically infected may develop serious liver disease that is not initially apparent. Chronic infection can ultimately lead to long-term liver damage, liver cancer, or liver failure—all of which can be fatal.


Health care providers review symptoms and can diagnose hepatitis B with a blood test or a combination of blood tests, which will reveal the presence of hepatitis B virus or antibodies to it.


There are no medicines for treating acute hepatitis B infection after a person acquires it. In milder cases, doctors usually prescribe rest, plenty of fluids, and a nutritious diet. While the body fights hepatitis B, a person should avoid any medications—over-the-counter or prescribed—that could damage the liver. Sufferers should also avoid alcohol during the recovery period, as alcohol may also damage the liver.

Chronic hepatitis B can be treated with certain medications, but most people will not have complications severe enough to require medication. Those with active liver disease may be prescribed one of several approved medications for preventing liver damage. Those who show no signs of liver damage should be monitored by a doctor to ensure that liver disease, should it occur, is found early.


The best way to prevent hepatitis B is to be vaccinated. The hepatitis B vaccine is usually administered in a series of three or four shots given over a six-month period. The vaccine is safe for adults and children and is routinely given to infants at birth.



National Institute of Allergy and Infectious Diseases, USA.