Hepatitis B Virus (HBV)

CPDTime.
6m

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.

What is Hepatitis B?

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).

What’s the Difference Between Hepatitis B and Other Hepatitis Viruses?

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).

  • Hepatitis A virus (HAV) is transmitted via exposure to the faeces of an infected person, usually through close direct contact or consumption of contaminated food or water. There is a vaccine available.
  • Hepatitis C virus (HCV) is usually spread via percutaneous exposure to the blood of an infected person. This most commonly occurs through sharing needles and injecting drug equipment. Sexual transmission is possible but less likely. There is no vaccine to prevent hepatitis C.
  • Hepatitis D virus (HDV) can only occur in those who have hepatitis B, either alongside HBV as a co-infection or as a ‘super-infection’.
  • Hepatitis E virus (HEV) is transmitted via exposure to the faeces of an infected person or animal, usually through the consumption of contaminated food or water. It is more common in developing countries.

(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).

How Does Hepatitis B Spread?

hepatitis b spread needlestick injury
Hepatitis B virus is transmitted when infectious bodily fluids enter the body, for example, through a needlestick injury.

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:

  • Unprotected sex with an infected person
  • Sharing needles or piercing equipment with an infected person
  • Sharing toothbrushes or razors with an infected person
  • Perinatal transmission (a pregnant mother with HBV spreading the virus to her baby)
  • A human bite from an infected person
  • During exposure-prone medical procedures
  • Needlestick injuries
  • Via organ transplantation or dialysis
  • Exposure to open sores on an infected person
  • Other exposure to the body fluids of an infected person.

(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).

Risk Factors for Hepatitis B

Those who are more at risk of being infected by HBV or developing chronic disease include:

  • Infants
  • Aboriginal and Torres Strait Islander peoples
  • Immunocompromised people (e.g. those living with HIV, those with impaired renal function, those on dialysis, those about to receive solid organ transplant and those who have received haematopoietic stem cell transplant)
  • People living with hepatitis C
  • People with chronic liver disease
  • Preterm and low-birthweight neonates
  • People who receive blood products
  • People living with developmental disabilities
  • People with occupations that increase their risk of acquiring hepatitis B (e.g. healthcare workers, police officers, armed forces members, emergency services staff, correctional facility workers, carers for people with developmental disabilities, funeral workers, embalmers, tattoo artists and body piercers)
  • Babies born to mothers who are HBsAg positive
  • Close contacts and sexual contacts of people with hepatitis B
  • Men who engage in sexual intercourse with men
  • Migrants from areas of the world that are hepatitis B–endemic, including North-East Asia, South-East Asia, Mediterranean Europe, North Africa, the Middle East, the Pacific Islands and Sub-Saharan Africa.
  • People who use injection drugs
  • Correctional facility inmates
  • Sex workers.

(AIH 2019; Better Health Channel 2021a)

Symptoms of Hepatitis B

hepatitis b symptoms jaundice

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:

  • Fever
  • Jaundice
  • Fatigue
  • Reduced appetite
  • Nausea and vomiting
  • Abdominal pain, particularly on the right side of the body under the ribcage
  • Muscle pain and tenderness
  • Urine that is dark in colour
  • Stools that are light in colour
  • Joint pain
  • Arthritis
  • Rash.

(AIH 2019)

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).

Chronic Hepatitis B

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).

Diagnosing Hepatitis B

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).

Treatment of Hepatitis B

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).

Preventing Hepatitis B

Hepatitis B Vaccine

hepatitis b vaccination

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.

Other Prevention Strategies

  • Having protected sex using condoms
  • Avoiding oral sex if one party has herpes, ulcers or bleeding gums
  • Covering open wounds and cuts with waterproof dressings
  • Avoiding sharing toothbrushes and razors with others
  • Ensuring you only get tattoos and body piercings from registered studios that properly sterilise their equipment
  • Avoiding sharing injection drug equipment and always ensuring needles and syringes have been sterilised
  • Wearing disposable gloves if providing first aid or making contact with blood or body fluids.

(DoH 2020; Better Health Channel 2021a)

Additional Resources


References

Test Your Knowledge

(Subscribers Only)

Question 1 of 3

Sally, a five-year-old child, has been infected with HBV. Which one of the following outcomes is most likely?

Start an Ausmed Subscription to unlock this feature!

Author