Incubation period
30 to 180 days, on average around 90.
When a test becomes reliable
A blood test picks it up from about 4 weeks, sometimes as late as 9.
Symptoms
- Often none at all, especially in children
- Yellowing of the skin and the whites of the eyes
- Dark urine and unusually pale stools
- Deep tiredness, nausea, no appetite, pain under the right ribs
- A long-term infection can be entirely silent for decades while quietly damaging the liver
Good to know
- It survives outside the body far better than HIV and is roughly 50 to 100 times easier to catch from blood
- A vaccine has existed since 1982 and is on the childhood schedule in most of Europe
- About 254 million people live with a long-term infection worldwide
- Whether an infection becomes long-term depends heavily on age at infection: most infants who catch it keep it, most adults clear it
How it was discovered
In 1965 Baruch Blumberg was studying blood proteins from populations around the world when he found an unexpected antigen in a sample from an Aboriginal Australian donor. He called it the Australia antigen and had no idea what it was; it turned out to be the surface of the hepatitis B virus. That accidental finding led to a blood test, then to a vaccine in 1981, and to a Nobel Prize for Blumberg in 1976.
Last updated: September 2026
This page is general information, not a diagnosis and not medical advice. Symptoms overlap between infections, and many infections have none at all — only a test can tell. If you think you have been exposed, talk to a doctor.