Hepatitis B is a serious disease caused by the hepatitis B virus, which attacks the liver. Hepatitis B can become a lifelong infection, leading to serious liver disease and even death. It is one of the most common causes of liver cancer around the world.

How hepatitis B is spread

The hepatitis B virus is spread when blood, body fluids (for example semen, vaginal fluids, saliva), or other fluids containing blood from a person infected with the virus enter the body of someone who is not infected. It can spread:

  • from a mother to her baby when she is pregnant or giving birth
  • through direct contact with the blood or open sores of an infected person
  • from sharing household items such as razors or toothbrushes
  • through unprotected sex
  • when unsterile equipment or techniques are used for tattooing, acupuncture or body piercing
  • from sharing needles or syringes during drug use

The virus can live outside the human body for at least seven days. During that time, the virus can still cause infection if it enters the body of a person who is not infected.

Risks of hepatitis B

There is no cure for hepatitis B. However, chronic hepatitis B can be treated. About 90% to 95% of people with hepatitis B get better and develop lifelong protection against the virus. However, the others remain infected and have the virus in their body for the rest of their lives. They are called “carriers” and may not display symptoms but can transmit the virus to others. These people are at high risk for serious health complications such as liver failure, permanent scarring of the liver (this is called “cirrhosis”) or liver cancer.

Infants, children and people with weak immune systems are more likely to become carriers, because their immune systems are unable to fight and clear the virus from their body. About 90% of infants infected with the hepatitis B virus will be infected for life.

Hepatitis B is not spread by casual contact such as hugging, kissing, shaking hands or by being around someone who is sneezing or coughing.

People who are infected with the hepatitis B virus often don’t know they have it. In fact, 50% of adults and 90% of children don’t have any symptoms. These people can easily pass it to someone else through contact with their blood or body fluids. In Canada, most cases occur in people who are 25 years of age or older and have not had the hepatitis B vaccination.


If people develop symptoms, they usually happen about 3 months after they have been infected, and include:

  • stomach pain or abdominal discomfort
  • fever
  • pain in the joints of the arms and legs
  • loss of appetite
  • nausea and vomiting
  • weakness and tiredness
  • dark-coloured urine
  • yellowing of the skin and the whites of the eyes (this is called “jaundice”)

Protection and prevention

You can protect against hepatitis B with a safe and effective vaccine. The vaccine is between 95% and 100% effective when you receive a complete series. The vaccine is given to children in Grade 7 as two separate shots 4 to 6 months apart, as well as to individuals who meet certain high-risk criteria.

Vaccination is the best way to protect against hepatitis B. Publicly funded hepatitis B vaccines are provided to specific populations, including school-age students, as well as people at higher risk due to their lifestyle, or due to being a contact, or having been diagnosed with acute liver disease.

Read or download the print-ready PDF version of this information.