Hepatitis B

What is Hepatitis B?
Hepatitis B is a viral infection that is caused by hepatitis B virus (HBV) and results in inflammation of the liver and liver disease (e.g. cirrhosis and liver cancer). It affects millions of people worldwide. It is a notifiable disease under the Infectious Diseases Regulations.

Where is Hepatitis B a problem?
Countries are classified as having low, intermediate, or high hepatitis B prevalence based on the percentage of the population positive for infection (shown by being positive for hepatitis B surface antigen (HBsAg) on a blood test).

Ireland, most countries in Western Europe, the United States, Canada, and Australia have a low hepatitis B prevalence (<2% HBsAg). Most countries in the Caribbean, South America, Central Europe, North Africa, and the Middle East have intermediate levels of hepatitis B (2-7% HBsAg). Almost all countries in Sub-Saharan Africa, and many countries in East and South-East Asia and Eastern Europe, have high levels of hepatitis B (≥8% HBsAg).

In low prevalence countries like Ireland, most infections are acquired sexually or through drug use. In high prevalence countries, hepatitis B is commonly spread from mother to child at birth or is acquired through exposure to infected blood from another child or family member in early childhood. Transmission in healthcare settings may also be important.

What are the symptoms of Hepatitis B infection?

The incubation period (time from infection to onset of symptoms) is 6 weeks to 6 months, the average being 2 to 3 months.

Not all those with acute HBV infection have symptoms. In fact, only up to 50% of adults and 10% of children develop symptoms when they are first infected. These symptoms include:

  • Fever
  • Fatigue
  • Nausea and vomiting
  • Loss of appetite.
  • Abdominal pain
  • Dark urine
  • Clay-coloured stools
  • Jaundice
  • Joint pain

In those with acute hepatitis B infection, symptoms lasting from a few weeks to several months.

What are the complications of chronic Hepatitis B?

Persistent (chronic) infection can occur in around 80-90% of infants infected in their first year of life, 30-50% of children infected before the age of 6 years, and <10% of people infected as adults.

Those who develop chronic infection are at increased risk of developing:

  • Chronic hepatitis (inflammation of the liver)
  • Cirrhosis (scarring of the liver)
  • Primary hepatocellular carcinoma (liver cancer)

This liver damage usually occurs gradually over 20-30 years and people with chronic infection may have mild symptoms or no symptoms for a long time. Premature death from chronic liver disease occurs in 15-25% of chronically infected people.

How is Hepatitis B spread?
Hepatitis B is spread when blood, semen or other body fluids from an infected person enter the body of a person who is not immune. This occurs in a variety of ways, including sexual contact with an infected person, transmission from an infected mother to her baby around the time of birth, sharing of needles and other drug paraphernalia by people who inject drugs, and sharing items that can break skin or mucous membranes (e.g. razors, toothbrushes, glucose monitoring equipment). 

Poor infection control practises in healthcare settings (e.g. dialysis units, diabetes clinics, needlestick injuries) can also spread hepatitis B.

You cannot get hepatitis A from sneezing, coughing, kissing, hugging, sharing cutlery or dishes, food, or water. 

Who is most at risk of Hepatitis B infection?

Although anyone can get hepatitis B, there are certain groups of people who are more at risk of getting infected. These include:

  • Infants born to HBsAg positive pregnant mothers
  • Those born in or travelling to countries with high hepatitis B prevalence
  • Men who have sex with men
  • Multiple sexual partners
  • Living in a household with an infected person
  • People who use recreational drugs
  • People with occupational risk of exposure
  • People with medical conditions that increase risk of exposure (e.g. on dialysis, diabetes, require blood transfusions)
  • People experiencing homelessness

How is Hepatitis B diagnosed?
Hepatitis B is diagnosed by testing the patient's blood for the presence of specific viral antigens or antibodies against the virus or by nucleic acid testing.

Specific tests might also be used to assess for the presence and extent of liver disease. This includes a physical examination, blood tests, and imaging scans.

Can Hepatitis B be treated?
There is no specific treatment for the acute hepatitis B infection. Therapy should be supportive and aimed at maintaining adequate nutritional balance.

Chronic hepatitis B infection can be treated with life-long antiviral medications. The aim of this treatment is to slow the occurrence and progression of liver disease, as well as to improve long term survival. However, the eradication of hepatitis B virus is rare. As a result, people with chronic hepatitis B infection should avoid alcohol and should ensure they are immunised against hepatitis A infection.

Concurrent infection with HIV occurs in 1% of those with HBV infection. This creates challenges when it comes to treating hepatitis B. As a result, WHO has recommended since 2015 that everyone diagnosed with HIV infection be treated with Ante-Retroviral Therapy (ART) for both infections. A Tenofovir-based regimen is the recommended therapy, as this covers both HIV and HBV. For more information, visit WHO’s Guidelines for the Prevention, Care and Treatment of Persons with Chronic Hepatitis B Infection.

How can Hepatitis B infection be prevented?

Hepatitis B infection can be prevented in different ways:

  • Use of standard precautions when handling human blood and body fluids and in situations where skin piercing equipment is used
  • Screening of blood donors for hepatitis B
  • Use of safe sex practices
  • Needle exchange programmes for people who inject drugs
  • Vaccination offered to infants and those at high risk of infection (see below for more information)

Hepatitis B vaccination
Hepatitis B is preventable with a vaccination. All those at increased risk of hepatitis B should receive the vaccination:

  • Occupational risk of exposure to blood or blood-contaminated environments
  • Family and household contacts
  • Those who use injectable drugs, as well as their contacts
  • Those at risk due to medical conditions (e.g. HIV, chronic kidney or liver disease, those that require frequent blood transfusions)
  • Men who have sex with Men(MSM)
  • Those with multiple sexual partners / who change partners frequently
  • Travellers to or from areas with a high or intermediate prevalence of hepatitis B virus

Infants receive 3 doses of the hepatitis B vaccine through the Irish Childhood Immunisation Schedule, which was started in 2008.

Hepatitis B can be passed from mother to child while the mother is pregnant. As a result, pregnant women should be screened for infection, and if she is hepatitis B positive, she might be asked to take antiviral medications during her pregnancy. Regardless of whether she takes this medication, all babies born to mothers with hepatitis B should receive a birth dose of the vaccine within 24 hours of delivery. 

More information is detailed in the Immunisation Guidelines for Ireland.

Other information:
HPSC: https://www.hpsc.ie/a-z/hepatitis/hepatitisb/
WHO:  https://www.who.int/en/news-room/fact-sheets/detail/hepatitis-b
CDC: https://www.cdc.gov/hepatitis/hbv/index.htm
Sexualwellbeing.ie: https://www.sexualwellbeing.ie/sexual-health/sexually-transmitted-infections/types-of-stis/hepatitis-b.html  

Last updated: 20 October 2023