Hepatitis B is a virus that causes both acute and chronic inflammation of liver cells. If left untreated, it can lead to cirrhosis and an increased risk of developing liver cancer.

Transmission of Hepatitis B(Note: The original Thai heading uses the word “screening” [การคัดกรอง], but the bullet points describe transmission methods.) It is transmitted through contact with infected bodily fluids, such as:

• Transmission from mother to child through contact with the mother’s blood during childbirth.
• Unprotected sexual intercourse.
• Body piercing or tattooing using improperly sterilized equipment.

Symptoms of Hepatitis B Infection

• Acute Infection: When the virus enters the body, some patients may experience body aches, fever, and jaundice (yellowing of the skin and eyes). If the body can successfully eliminate the virus, symptoms will improve within 2-3 weeks, and the body will build immunity against the disease without it progressing to a chronic infection.
• Chronic Infection: Patients often show no symptoms. The infection can be diagnosed via a blood test detecting the virus. If the infection leads to complications, patients may present with symptoms of impaired liver function, such as an enlarged abdomen, swollen legs, and jaundice.

Diagnosis of Hepatitis B Diagnosis is made by detecting the virus in the blood through an antigen test (HBsAg).

Complications of Hepatitis B

• Liver Cirrhosis: Caused by repeated inflammation that leads to the formation of fibrosis (scar tissue) in the liver.
• Acute Liver Failure: Caused by severe inflammation and death of liver tissue, resulting in decreased liver function.
• Liver Cancer: Patients with untreated Hepatitis B have, on average, a 100 times higher risk of developing liver cancer compared to healthy individuals.

Who Should Receive the Hepatitis B Vaccine & Risk Reduction

• Individuals at high risk of exposure should receive the preventive vaccine.
• Risk can be reduced by avoiding risky sexual behaviors (e.g., using condoms) and avoiding sharing needles with others.

Additional Tests After a Hepatitis B Diagnosis

• Blood tests to evaluate liver function (Liver Function Test – LFT).
• Testing to measure the amount of virus in the blood (HBV viral load).
• Testing to measure liver stiffness/scarring (Transient elastography/FibroScan).
• Ultrasound to assess for cirrhosis and screen for liver cancer.

Prevention of Hepatitis B Infection Those who should receive the Hepatitis B vaccine include:

• Patients with chronic liver disease.
• Patients with chronic kidney failure.
• Individuals whose blood tests show no immunity and no current infection.

Treatment for Hepatitis B Current antiviral medications are highly effective at controlling the viral load, though the chance of completely eliminating the virus from the body remains relatively low. Furthermore, some patients may not necessarily need antiviral medication. Patients who have clear indications for antiviral treatment include those with cirrhosis, high levels of liver fibrosis, a high viral load, and patients with liver cancer.