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Diseases / Hepatitis B

Hepatitis B

What is it?: 

Disease caused by Hepatitis B Virus (HBV) has a worldwide distribution. Based on serological data, it was estimated that in 1995 more than 2 billion people globally had evidence of past or present HBV infection. In 2015 the global prevalence of HBV infection in the general population was estimated at 3.5% with about 257 million persons living with chronic HBV infection. Chronically infected persons are at high risk for development of liver cirrhosis and hepatocellular carcinoma (HCC).1

Most of the burden of HBV-related disease results from infections acquired in infancy through perinatal or early childhood exposure to HBV because infection acquired at an early age is more likely to become chronic than infection acquired later in life.1

Major progress in the global response to viral hepatitis has been achieved through the expansion of routine hepatitis B vaccination, which was facilitated by the introduction of new combination vaccines.1

Clinical features: 

The virus can cause acute hepatitis. Fewer than 5% of infected children under 5 years of age and 30-60% of infected adults are symptomatic. Common presentations include fever, loss of appetite, nausea, vomiting, abdominal pain, yellow coloring of the eyes, dark urine and clay colored or light stools.

Symptomatic or not, approximately 5-10% of adults and 95% of perinatally infected infants are unable to clear the virus, thus becoming chronic carriers. They may subsequently develop chronic hepatitis, permanent liver damage or liver cancer.2

Mode of transmission: 

Hepatitis B virus can be found in blood and body fluids of an infected person. It is spread in the following ways:2

  1. Mother to infant transmission at or around the time of delivery
  2. Blood contact
    1. by direct contact with contaminated blood
    2. by sharing contaminated personal items such as toothbrushes, razors and nail cutters
    3. by sharing contaminated needles
    4. by ear-piercing, tattooing or acupuncture using contaminated instruments
    5. by transfusion of contaminated blood or blood products
  3. Sexual contact2
Incubation period: 

The incubation period ranges from 45-160 days. Symptoms usually occur within 3 months.2

Prevention: 
  1. Avoid sharing of syringes, razors, toothbrushes and other objects that may be contaminated with blood.2
  2. Clean and dress wound adequately. 2
  3. Wear gloves while handling blood and body fluids. 2
  4. Disinfect objects contaminated with blood using household bleach diluted 4 times. 2
  5. Practice safe sex. 2
  6. An effective vaccine against hepatitis B infection is available. The standard vaccination scheme is a 3-dose schedule administered at 0, 1, 6 months. Booster dose is usually not required for those who have completed a standard three-dose regimen. 2
  7. For babies born to carrier mothers, an additional hepatitis B immunoglobulin is given within 24 hours of birth to prevent transmission of infection from their mothers. 2
Managment: 

For management of acute hepatitis, the patient should have adequate rest, balanced diet and avoid alcohol intake. Safer sex and practices to avoid transmission via blood contact should be encouraged. Minority of adults who might become chronic carriers should receive individualized medical care for chronic hepatitis B infection.2

Reference:

  1. World Health Organization. Weekly epidemiological record. Hepatitis B vaccines: WHO position paper - July 2017. 2017;27(92):369-392.
  2. CHP. https://www.chp.gov.hk/en/healthtopics/content/24/27.html Accessed on 8Feb2021

MAT-HK-2100166-1.0-02/2021