Only some people with hepatitis B experience symptoms, which usually develop 2 or 3 months after exposure to the hepatitis B virus.

Many people infected in adulthood will not experience any symptoms and will fight off the infection without realising they had it.

But they'll still be able to pass the virus on to others while they're infected.

Find out more about how hepatitis B is spread

Main symptoms of hepatitis B

Symptoms of hepatitis B can include:

• tiredness
• general aches and pains
• high temperature
• a general sense of feeling unwell
• loss of appetite
• feeling and being sick
• diarrhoea
• tummy pain
• yellowing of the skin and eyes (jaundice)
• dark urine and pale, grey-coloured poo

Many of these symptoms can be mistaken for more common illnesses, such as flu or gastroenteritis.

How long do symptoms of hepatitis B last?

Hepatitis B in adults will usually pass within 1 to 3 months. This is known as acute hepatitis B and rarely causes any serious problems.

Occasionally, the infection can last for 6 months or more. This is known as chronic hepatitis B.

Chronic hepatitis B mainly affects babies and young children who get hepatitis B. It's much less common in people who become infected later in childhood or when they're an adult.

The symptoms of chronic hepatitis B tend to be quite mild and may come and go. Some people may not have any noticeable symptoms.

But without treatment, people with chronic hepatitis B can develop problems like scarring of the liver (cirrhosis).

Read more about treatments for hepatitis B and complications of hepatitis B.

Hepatitis B is an infection caused by the hepatitis B virus. The virus is found in the blood and bodily fluids of an infected person.

Many people with hepatitis B have few symptoms and may not know they're infected. They may spread the infection without realising it.

Hepatitis B is most often caught in parts of the world where the infection is more common, although certain groups of people are at risk of picking up the infection in the UK.

How hepatitis B is spread

Hepatitis B can be spread by:

• a mother to her newborn baby, particularly in countries where the infection is common – all pregnant women in the UK are offered screening for hepatitis B; babies of infected mothers are vaccinated immediately after birth to help prevent infection
• injecting drugs and sharing needles and other drug equipment, such as spoons and filters
• having sex with an infected person without using a condom
• having a tattoo, body piercing, or medical or dental treatment in an unhygienic environment with unsterilised equipment
• having a blood transfusion in a country where blood is not tested for hepatitis B – all blood donations in the UK are now tested for the infection
• sharing toothbrushes or razors contaminated with infected blood
• the skin being accidentally punctured by a used needle (needle stick injury) – this is mainly a risk for healthcare workers
• the blood of someone with hepatitis B getting into an open wound, cut or scratch – in rare cases, being bitten by someone with hepatitis B can also spread the infection

Hepatitis B is not spread by kissing, holding hands, hugging, coughing, sneezing or sharing crockery and utensils.

Who's most at risk of hepatitis B

People at highest risk of hepatitis B include:

• people born or brought up in a country where the infection is common
• babies born to mothers infected with hepatitis B
• people who have ever injected drugs
• anyone who has had unprotected sex, including anal or oral sex – particularly people who have had multiple sexual partners, people who have had sex with someone in or from a high-risk area, men who have sex with men, and commercial sex workers
• close contacts, such as family members, of someone with a long-term (chronic) hepatitis B infection

The risk of getting hepatitis B for travellers going to places where the infection is common is generally considered to be low if these activities are avoided.

Your GP can arrange for you to have a blood test to check for hepatitis B and have the hepatitis B vaccination if you're at a high risk.

High-risk areas

Hepatitis B is found throughout the world, but is particularly common in:

• sub-Saharan Africa
• east and southeast Asia
• the Pacific Islands
• parts of South America
• southern parts of eastern and central Europe
• the Middle East
• the Indian subcontinent

Most new cases of hepatitis B in the UK occur in people who caught the infection in one of these areas before moving to the UK.

Treatment for hepatitis B depends on how long you have been infected for:

• short-term (acute) hepatitis B does not usually need specific treatment, but may require treatment to relieve the symptoms
• long-term (chronic) hepatitis B is often treated with medication to keep the virus under control

Emergency treatment can also be given soon after possible exposure to the hepatitis B virus to stop an infection developing.

Emergency hepatitis B treatment

See your GP as soon as possible if you think you may have been exposed to the hepatitis B virus.

To help stop you becoming infected, they can give you:

• a dose of the hepatitis B vaccine – you'll also need 2 further doses over the next few months to give you long-term protection
• hepatitis B immunoglobulin – a preparation of antibodies that work against the hepatitis B virus and can offer immediate but short-term protection until the vaccine starts to take effect

These are most effective if given within 48 hours after possible exposure to hepatitis B, but you can still have them up to a week after exposure.

Treatment for acute hepatitis B

If you're diagnosed with hepatitis B, your GP will usually refer you to a specialist, such as a hepatologist (liver specialist).

Many people do not have any troublesome symptoms, but if you do feel unwell, it can help to:

• get plenty of rest
• take over-the-counter painkillers, such as paracetamol or ibuprofen, for tummy pain
• maintain a cool, well-ventilated environment, wear loose clothing, and avoid hot baths or showers if itching is a problem
• take medication, such as metoclopramide, to stop you feeling sick, and chlorphenamine to reduce itching – your doctor can give you a prescription for these if necessary

Most people recover completely in a couple of months, but you'll be advised to have regular blood tests to check that you're free of the virus and have not developed chronic hepatitis B.

Treatment for chronic hepatitis B

If blood tests show that you still have hepatitis B after 6 months, your doctor may recommend medication to reduce the risk of complications of hepatitis B and regular tests to assess the health of your liver.

Treatment is usually offered if:

• your immune system is unable to control the hepatitis B by itself
• there's evidence of ongoing liver damage

Hepatitis B medications can help keep the virus under control and stop it damaging your liver, although they will not necessarily cure the infection and some people need lifelong treatment.

The main medicines for chronic hepatitis B include peginterferon alfa 2-a and antiviral medicines.

Peginterferon alfa-2a

If your liver is working fairly well, the first treatment offered is usually a medicine called peginterferon alfa 2-a.

This stimulates the immune system to attack the hepatitis B virus and regain control over it. It's usually given by injection once a week for 48 weeks.

Common side effects include flu-like symptoms, such as a fever and muscle and joint pain, after you start to take the medicine, although these should improve with time.

Tests will be carried out during treatment to see how well it's working. Alternative medicines may be recommended if it's not helping.

Antiviral medicines

If your liver is not working well, or peginterferon alpha-2a is not suitable or not working for you, your doctor may recommend trying antiviral medication instead.

This will usually be either tenofovir or entecavir, both of which are taken as tablets.

Common side effects of these medicines include feeling sick, vomiting and dizziness.

Living with hepatitis B

If you have hepatitis, you should:

• avoid having unprotected sex, including anal and oral sex, unless you're sure your partner has been vaccinated against hepatitis B
• avoid sharing needles used to inject drugs with other people
• take precautions to avoid the spread of infection, such as not sharing toothbrushes or razors with other people (close contacts, such as family members, may need to be vaccinated)
• eat a generally healthy, balanced diet – there's no special diet for people with hepatitis B
• avoid drinking alcohol – this can increase your risk of developing serious liver problems
• speak to your doctor if you're thinking of having a baby

People with hepatitis B can usually have a healthy pregnancy, but it's a good idea to discuss your plans with a doctor first as you may need extra care and your medications may need to be changed.

There's a risk of pregnant women with hepatitis B passing the infection on to their child around the time of the birth, but this risk can be reduced by ensuring the baby is vaccinated shortly after they're born.

People with hepatitis B can sometimes develop serious liver problems. These mostly affect people with an untreated long-term (chronic) infection.

Some of the main problems associated with hepatitis B include:

Cirrhosis

Scarring of the liver (cirrhosis) affects around 1 in 5 people with chronic hepatitis B, often many years after they first got the infection.

Cirrhosis does not usually cause any noticeable symptoms until extensive damage to the liver has occurred, when it can cause:

• tiredness and weakness
• loss of appetite
• weight loss
• feeling sick
• very itchy skin
• tenderness, pain or swelling in the tummy
• swelling of the ankles

There's currently no cure for cirrhosis, although it's possible to manage the symptoms and slow its progression. 

If the liver becomes severely damaged, a liver transplant may be needed.

Find out more about the treatments for cirrhosis

Liver cancer

People with cirrhosis caused by hepatitis B have around a 1 in 20 chance of developing liver cancer every year.

Symptoms of liver cancer include:

• unexplained weight loss
• loss of appetite
• feeling very full after eating, even if the meal was small
• feeling and being sick
• yellow skin and eyes (jaundice)

Treatment for liver cancer may involve surgery to remove the affected section of liver, a procedure to destroy the cancerous cells, or a liver transplant.

Find out more about the treatments for liver cancer

Fulminant hepatitis B

In less than 1 in 100 cases, short-term (acute) hepatitis B can lead to a serious problem called fulminant hepatitis B.

This is where the immune system attacks the liver and causes extensive damage to it.

It can lead to symptoms such as:

• confusion
• collapsing
• swelling of the tummy caused by a build-up of fluid
• severe jaundice

Fulminant hepatitis B can cause the liver to stop working properly and is often fatal if not treated quickly.