What to know about hepatitis B virus

The virus infects liver cells. Infection may be short-lived or may remain in the body and require ongoing monitoring to check liver health. A person can carry and transmit hepatitis B without feeling unwell, so symptoms alone cannot confirm or exclude infection.

Transmission can occur through contact with infected blood, sex without barrier protection, shared injecting equipment, non-sterile tattoo or piercing equipment, or from a pregnant person to their baby around birth. It does not spread through coughing, sneezing, hugging, or sharing ordinary meals. Hepatitis B can present with fatigue, poor appetite, nausea, abdominal discomfort, dark urine, pale stools, joint aches, or yellowing of the skin or eyes.

Arrange testing after a possible exposure, during pregnancy, or if a clinician recommends screening based on your medical or family history. Blood tests can identify infection and immunity; liver tests and other assessments may be used when infection is found.

Vaccination can prevent hepatitis B but does not treat an existing infection. Until your status is clear, do not share razors, toothbrushes, needles, or anything that may carry blood; cover cuts; use barrier protection during sex; and tell clinicians who may handle your blood. Do not donate blood if you have hepatitis B. If diagnosed, attend planned monitoring and check with your clinician before taking herbal remedies, supplements, or medicines that could affect the liver.

Seek prompt medical advice after a needlestick injury, unprotected sexual exposure, or contact between another person's blood and broken skin or mucous membranes. Time-sensitive preventive treatment may be considered, so do not wait for symptoms to develop.

Use urgent or emergency services for confusion, extreme sleepiness, vomiting blood, black stools, a rapidly swelling abdomen, fainting, severe weakness, or yellow skin or eyes accompanied by persistent vomiting. These features may signal significant liver dysfunction or bleeding and require direct assessment.

Clarify which blood tests you need, what each result says about infection or immunity, whether vaccination is appropriate, and whether household or sexual contacts need testing. If infection is confirmed, ask how liver health will be monitored, whether treatment is indicated, and what to do when planning a pregnancy.