Hepatitis B: Symptoms, Treatment, and Chronic Risk in Singapore

Hepatitis B is a viral infection of the liver caused by the hepatitis B virus (HBV). It can be acute (short-term) or become chronic (long-term), with chronic infection potentially leading to cirrhosis, liver failure, or liver cancer over decades. Hepatitis B spreads through blood and body fluids, including sexual contact and from mother to baby at birth. Singapore has historically had a chronic hepatitis B prevalence of around 4%, making screening and vaccination important.

Many people with acute hepatitis B have no symptoms or only mild ones. When symptoms occur (typically 1 to 4 months after exposure), they may include fatigue, loss of appetite, nausea, upper-right abdominal pain, dark urine, pale stools, and jaundice (yellowing of the skin and eyes). Chronic hepatitis B is often silent for decades, with symptoms appearing only once advanced liver damage has developed. This is why testing is important even when you feel well.

Hepatitis B is transmitted through blood and body fluids. Common routes include unprotected sexual contact (vaginal, anal, or oral), sharing needles or drug equipment, mother-to-baby transmission during childbirth, unsterilised medical or tattoo equipment, and rarely shared razors or toothbrushes contaminated with blood. Hepatitis B is not spread through casual contact such as hugging, sharing meals, coughing, or sneezing.

Hepatitis B is diagnosed through blood tests that measure hepatitis B serology and viral load. Key markers include HBsAg (current infection), anti-HBs (immunity from vaccination or past infection), anti-HBc (past or current exposure), HBeAg and HBV DNA (active viral replication), and ALT and AST (liver function). The pattern of results helps your doctor determine whether you have a current infection, past infection, vaccine-induced immunity, or need further evaluation.

Acute hepatitis B usually clears on its own in adults: about 90 to 95% of adult infections resolve fully with supportive care. Chronic hepatitis B cannot currently be cured but can be controlled with oral antiviral medication (such as entecavir or tenofovir) that suppresses the virus, slows liver damage, and reduces the risk of liver cancer. Some patients with chronic hepatitis B need long-term antiviral treatment, while others require regular monitoring before treatment is started.

Yes. About 5 to 10% of adult acute hepatitis B infections become chronic, but the risk is much higher in babies infected at birth (around 90%) and young children, which is why universal infant vaccination is so important. Chronic hepatitis B can silently damage the liver over decades, causing cirrhosis, liver failure, or liver cancer (hepatocellular carcinoma). Singapore has historically reported chronic hepatitis B prevalence around 4%, and routine monitoring helps detect complications early.

"Carrier" is an older, common term for someone with chronic hepatitis B, meaning HBsAg remains positive for more than 6 months. Carriers can pass the virus to others through blood and body fluids, even if they feel well and have no symptoms. Many have an "inactive" form with low viral activity and minimal liver damage, while others have ongoing inflammation that needs treatment. Regular monitoring (every 6 to 12 months) is recommended.

Yes. Mother-to-baby (vertical) transmission is a major route, and without intervention, the risk is high. In Singapore, all pregnant women are screened for HBsAg as part of routine antenatal care. If the mother is positive, the baby receives hepatitis B immunoglobulin and the first dose of the hepatitis B vaccine within hours of birth, followed by the standard infant vaccine series. This combined approach prevents transmission in most cases.

Yes. The hepatitis B vaccine is highly effective when the full series is completed and is part of routine childhood immunisation in Singapore. Adults without prior vaccination can complete a 3-dose series (0, 1, and 6 months). Other prevention measures include using condoms during sex, not sharing needles or personal items that may have blood on them, and ensuring tattoo and medical equipment is properly sterilised. See our hepatitis B vaccine page for full details.

Mediway Medical Centre offers hepatitis B blood testing, immunity checks, pre-vaccination assessment, vaccination, and GP review at our Clarke Quay clinic. Patients with chronic hepatitis B may be referred for specialist liver care where appropriate. For comprehensive STI screening, see our STD test page. Book a consultation through our online booking, WhatsApp, or call 6909 0190.