Most people remain healthy without any symptoms while they fight off the virus. Some will not even know they have been infected.
However, until the virus has been cleared from their body, they can pass it on to others.
If there are any symptoms, these will develop on average 40 to 160 days after exposure to the virus and will usually pass within one to three months.
Symptoms of hepatitis B include:
- flu-like symptoms, such as tiredness, general aches and pains, headaches and a high temperature of 38ºC (100.4ºF) or above
- loss of appetite and weight loss
- feeling sick
- being sick
Some people may experience more severe symptoms, including abdominal pain and yellowing of the skin and eyes (jaundice).
Jaundice happens because your damaged liver is unable to remove bilirubin, a yellow substance in the blood that is a by-product of red blood cells. Bilirubin may also turn your urine very dark, and you may have pale stools (faeces).
Chronic hepatitis B
Hepatitis B is said to be chronic when you have been infected for longer than six months.
The symptoms are usually much milder and tend to come and go. In many cases, people with chronic hepatitis B infection will not experience any noticeable symptoms.
However, without treatment, chronic hepatitis B can lead to more serious conditions such as liver disease (inflammation) or cirrhosis (scarring of the liver) in a small number of people.
Read more about complications of hepatitis B.
When to seek medical advice
Always make an appointment to see your GP if you have unusual symptoms that persist for more than a few days. Ask your GP for a hepatitis B test if you think you may have been exposed to hepatitis B in the past.
When to seek immediate medical advice
If you suspect that you have been recently exposed to the hepatitis B virus, seek immediate medical advice.
It is possible to prevent infection with treatment, but to be most effective it should be given in the first 48 hours after exposure (although it can sometimes be effective up to a week after exposure).
Phone your GP as soon as possible. If this is not possible, telephone NHS 111 or your local out-of-hours service for advice.