Hepatitis B: A Hidden Danger You Might Overlook, and How to Protect Yourself

Hepatitis B is caused by infection with the hepatitis B virus (HBV). The hepatitis B virus is a DNA virus belonging to the family Hepadnaviridae. Worldwide, there are approximately 240 million people living with hepatitis B, with prevalence ranging from 2 - 8% depending on the country. In Thailand, an estimated 7 - 8 million people are carriers of the hepatitis B virus, making it a very significant health concern. In recent years, however, after the hepatitis B vaccine was introduced for all newborns, the incidence among Thai people has fallen to approximately 3 - 5 percent.

How hepatitis B is transmitted

• Sexual contact with an infected person without using a condom or other protection
• Sharing personal items with others when body fluids are involved, such as saliva or lymph
• Mother-to-child transmission during pregnancy
• Sharing needles with others, using needles for drug use, or being pricked by a needle
• Exposure to blood or body fluids, such as through blood donation or through an open wound

Symptoms of hepatitis B infection

• Acute hepatitis B causes symptoms such as fatigue, low-grade fever, loss of appetite, and nausea or vomiting, sometimes with discomfort at the pit of the stomach (epigastric area) or the upper right abdomen. Later, jaundice and dark urine appear, and the liver becomes severely inflamed. It then gradually improves and returns to normal, though the eyes may remain yellow for some time afterward. At this stage, recovery can occur on its own, but in some people the liver inflammation can become severe and the liver can deteriorate rapidly, leading to complications.
• Chronic hepatitis B often causes no symptoms and cannot resolve on its own. People with chronic hepatitis B who do not receive regular medical follow-up are at risk of developing cirrhosis and liver cancer.

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Diagnosing hepatitis B infection

An initial assessment can be made at home by observing symptoms as they appear, such as nausea or vomiting, fever, abdominal pain, and yellowing of the skin and eyes. If you find that you may be at risk or have symptoms of hepatitis B, see a doctor. The doctor will make a diagnosis through blood tests, including a liver function test, a blood test for the hepatitis B virus, and possibly a liver tissue biopsy for examination.

• HBsAg (hepatitis B surface antigen): a positive result means the patient currently has the hepatitis B virus.
• Anti-HBs (immunity to HBsAg): a positive result means the patient is immune to the hepatitis B virus. Immunity develops either after receiving the vaccine or after a previous hepatitis B infection from which the person has recovered. People who are immune therefore do not transmit the virus to others and cannot be reinfected with hepatitis B.

Complications of hepatitis B

• Chronic hepatitis: this occurs when the body is unable to clear the virus, leading to ongoing liver inflammation, which can progress to cirrhosis and liver cancer.
• Cirrhosis: this occurs when the liver is permanently damaged and can no longer function normally. People often experience fatigue, loss of appetite, weight loss, abdominal pain, and swelling of the body.
• Liver cancer: liver cancer is the most common cancer in Thailand. People often experience fatigue, loss of appetite, weight loss, abdominal pain, and swelling of the body.

Treatment for hepatitis B

Currently, the medications used to treat hepatitis B fall into two groups: injectable pegylated-interferon alpha and oral nucleoside/nucleotide analogs. The distinguishing features of these two treatment approaches are as follows.

Injectable pegylated-interferon alpha

• Acts as an immunomodulator with the goal of achieving long-term immunological control, so HBV resistance is not a concern
• Has a fixed treatment duration
• Side effects are common, such as flu-like symptoms, fatigue, mood disturbances, cytopenias, and autoimmune disorders
• Cannot be used in patients with decompensated cirrhosis
• The decision to use this class of drug should draw on additional information, such as HBV DNA, HBeAg, or HBsAg titer, to help assess the likelihood of response to treatment

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Oral nucleoside/nucleotide analogs

• Act by inhibiting viral replication, which may lead to HBV resistance after a period of treatment. This class is divided into two subgroups based on the likelihood of HBV resistance: low barrier to resistance (lamivudine, adefovir, and telbivudine) and high barrier to resistance (entecavir, tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF))
• There is no fixed treatment duration; the medication is taken until the treatment endpoint is reached, which is HBeAg seroconversion in HBeAg-positive patients or HBsAg loss/seroconversion in HBeAg-negative patients
• Side effects can occur but are usually not severe, such as with lamivudine (pancreatitis, lactic acidosis) or TDF (nephropathy, Fanconi syndrome, osteomalacia, lactic acidosis)
• This is the main treatment in many clinical settings, such as post-liver transplantation, severe chronic HBV exacerbation, or prevention of HBV reactivation in patients receiving immunosuppressive therapy

Caring for yourself when living with hepatitis B

1. Get enough rest and sleep
2. Do light exercise, but avoid overexertion
3. Eat nutritious foods, and avoid high-fat foods, smoked meats, and grilled foods that are burnt or charred
4. Avoid alcohol
5. See your doctor as scheduled for regular blood tests
6. Use a condom during sex
7. Avoid donating blood until your doctor advises that it is safe to do so

Preventing hepatitis B

The best way to prevent hepatitis B infection is to build immunity to the virus by receiving the hepatitis B vaccine, which produces immunity in most people. Once immunity is established, it usually protects against infection for life. You can also protect yourself with everyday precautions, such as keeping yourself healthy, avoiding excessive worry or stress, using a condom every time you have sex, and, if you want to get your ears pierced or get a tattoo, choosing a reputable shop that follows proper hygiene standards.

Read other articles related to hepatitis B

• Don't wait until it's too late: understanding hepatitis B
• Hepatitis B: symptoms, causes, treatment, and prevention

Hepatitis B is a disease caused by infection with the hepatitis B virus, which can be transmitted through blood, semen, and other body fluids such as lymph. You can prevent hepatitis B infection by receiving the hepatitis B vaccine, avoiding high-risk behaviors, and protecting yourself from contact with the blood or body fluids of someone who is infected.

Verified references

Links and relevance to the article’s main topic were reviewed on 13 August 2026. Each source supports only the scope stated in the original document and does not replace personalised medical, legal, or service advice.

1. WHO: Hepatitis B fact sheet Accessed 13 August 2026