Hepatitis B Virus (HBV)
Published: 27 May 2021
Published: 27 May 2021
About 230 000 Australians are estimated to be living with chronic hepatitis B (AIH 2019).
Despite this, hepatitis B is a largely preventable condition.
Hepatitis B is a viral infection causing inflammation of the liver. It develops upon being infected with the hepatitis B virus (HBV), which is one of the five main hepatitis viruses along with types A, C, D and E (WHO 2019).
Upon entering the body, the HBV virus multiples in the liver, triggering an immune response that damages and kills the hepatocytes (liver cells) (AMBOSS 2021).
Hepatitis B is a serious condition that has the potential to cause long-lasting damage and complications. While there is no cure, symptoms can be managed and in many cases will resolve on their own. However, some people with hepatitis B become chronically ill (DoH 2020).
It’s important to remember that hepatitis A, B, C, D and E are different illnesses caused by different viruses. While they all cause liver infection, they are not the same and should not be treated as interchangeable (WHO 2019).
(WHO 2019; CDC 2020; Better Health Channel 2021b)
Among these types of hepatitis, A, B and C are the most common in Australia (Better Health Channel 2021b).
HBV is found in body fluids - primarily blood, along with semen, vaginal secretions, menstrual fluids and saliva (Better Health Channel 2021a; WHO 2020).
The virus is spread by infectious body fluids entering the body via percutaneous (a puncture through the skin), mucosal (through the mucus membranes), or non-intact skin exposure (CDC 2020).
A person with acute hepatitis B is contagious as long as the hepatitis B surface antigen (HBsAg) is present in their blood, which is usually for a period of four to five months. Those with chronic hepatitis B are usually contagious for the rest of their life (AIH 2019).
Ways that HBV can spread include:
(DoH 2020; WHO 2020; CDC 2020)
Note that HBV cannot be transmitted via sharing food, drinks and eating utensils with someone who has the virus (Cancer Council NSW 2020).
Between 30 and 40% of hepatitis B infections have no known cause (Better Health Channel 2021a).
HBV is able to survive outside the body for seven days or more and can still infect others during this timeframe (WHO 2020).
Those who are more at risk of being infected by HBV or developing chronic disease include:
(AIH 2019; Better Health Channel 2021a)
The incubation period of hepatitis is typically two to three months after contracting the HBV virus (DoH 2020).
Many HBV infections are asymptomatic, particularly in young children and infants. Only about 30 to 50% of adults and 10% of children will develop symptoms (AIH 2019; SA Health 2020).
Those who are symptomatic may experience:
These symptoms are typically the same as those caused by other types of hepatitis (AIH 2019).
An acute hepatitis B infection persists for up to six months (SA Health 2020).
Following an acute episode of hepatitis B, there is a risk that the patient will become chronically infected with HBV. This occurs very rarely in adults but is a common complication for infants (AIH 2019).
The likelihood of chronic hepatitis B developing is as follows:
|Age of exposure to HBV||Acute hepatitis B||Chronic hepatitis B|
|Infants < 1 year of age||Most patients will not experience acute symptoms||90% of patients will develop chronic hepatitis B|
|Children aged 1 to 6||Most patients will not experience acute symptoms||30% of patients will develop chronic hepatitis B|
|Adults and children aged over 6||Most patients will experience acute symptoms||Up to 10% of patients will develop chronic hepatitis B|
(Adapted from Hepatitis Australia 2020; AIH 2019)
Therefore, adults are more likely to experience symptomatic acute hepatitis B but are less likely to develop chronic hepatitis B, while children are less likely to experience symptomatic acute hepatitis B but much more likely to develop chronic hepatitis B.
While many people living with chronic hepatitis B are asymptomatic, they are at increased risk of complications such as cirrhosis (liver scarring) and liver cancer that may develop later on in life without any previous signs of ill health (Better Health Channel 2021a). These complications pose a high risk of death (WHO 2020).
People living with chronic hepatitis B are also still infectious to others and may not be aware that they are carrying the virus (AIH 2019).
Groups with a high prevalence of chronic hepatitis B in Australia include Aboriginal and Torres Strait Islander peoples, people living with HIV, people who used injection drugs 1980 and 1990, and close contacts of people who were diagnosed with hepatitis B between 1980 and 1990 (AIH 2019).
Hepatitis B is diagnosed with blood tests to detect the presence of HBsAg (WHO 2020).
All pregnant women are tested for hepatitis B due to the high risk of perinatal transmission (Better Health Channel 2021a).
As there is no specific cure for hepatitis B, treatment involves symptom management and rest. Acute hepatitis B will eventually resolve on its own (DoH 2020).
Asymptomatic people living with chronic hepatitis B often do not require treatment but will need routine check-ups to monitor their liver for damage. Those who have signs of liver damage may require antiviral medicines and regular screening for liver cancer (Healthdirect 2020).
The best way to prevent hepatitis B is through vaccination against the HBV virus. Immunisation is recommended for all infants and high-risk groups of people (those listed under the ‘Risk Factors for Hepatitis B’ section above) (Better Health Channel 2021a).
Under the National Immunisation Program, some groups are eligible for free immunisation against HBV (Better Health Channel 2021a).
95% of people who have received a full HBV vaccination course will be protected from hepatitis B (Healthdirect 2020).
You can find more information about the hepatitis B vaccine in the Australian Immunisation Handbook.
(DoH 2020; Better Health Channel 2021a)
Question 1 of 3
Sally, a five-year-old child, has been infected with HBV. Which one of the following outcomes is most likely?
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