Hepatitis B

16 min read

What is hepatitis B?

Hepatitis B is a type of virus that can infect the liver.

Symptoms can include:

  • feeling sick
  • being sick
  • lack of appetite
  • flu-like symptoms, such as tiredness, general aches and pains, headaches
  • yellowing of the skin and eyes (

However, many people don’t realise they have been infected with the virus, because the symptoms may not develop immediately, or even at all.

Read more about

the symptoms of hepatitis B

It takes between 40 and 160 days for any symptoms to develop after exposure to the virus.

How does hepatitis B spread?

Hepatitis B can be spread through blood and body fluids such as semen and vaginal fluids, so it can be caught:

  • during unprotected sex, including anal and oral sex
  • by sharing needles to inject drugs such as heroin

Hepatitis B in pregnancy

A mother can also pass on the hepatitis B infection to her newborn baby, but if the baby is vaccinated immediately after birth (see below), the infection can be prevented.

People who are most at risk of contracting hepatitis B include the following:

  • people who inject drugs
  • people who change sexual partners frequently

Read more about the

causes and risk factors for the hepatitis B infection

How is it diagnosed?

Hepatitis B is diagnosed by a

blood test
that shows a positive reaction to hepatitis B surface antigen (the outer surface of the hepatitis B virus that triggers a response from your immune system). A positive result means your body is making antibodies to try and fight the hepatitis B virus.

Your doctor may also request a liver function test. This is a blood test that measures certain enzymes and proteins in your bloodstream, which indicates whether your liver is damaged. It will often show raised levels if you are infected with the hepatitis B virus.

Stages of infection

In most cases, the hepatitis B virus will only stay in the body for around one to three months. This is known as acute hepatitis B.

In around 1 in 20 cases in adults, the virus will stay for six months or longer, usually without causing any noticeable symptoms. This is known as chronic hepatitis B.

Chronic hepatitis B is particularly common in babies and young children: 9 in 10 children infected at birth and around 1 in 5 children infected in early childhood will develop a long-term infection.

People with chronic hepatitis B can still pass the virus on to other people, even if it is not causing any symptoms.

Around 20% of people with chronic hepatitis B will go on to develop scarring of the liver (

), which can take 20 years to develop, and around 1 in 10 people with cirrhosis will develop
liver cancer

Read more about

complications of hepatitis B

How is it treated?

There is currently no specific treatment for acute hepatitis B, other than using painkillers to relieve symptoms.

Treatment for chronic hepatitis B depends on how badly your liver is affected. It can be treated using medications designed to slow the spread of the virus and prevent damage to the liver.

Read more about the

treatment of hepatitis B

Can it be prevented?

There is a vaccine that is thought to be 95% effective in preventing hepatitis B. Vaccination would usually only be recommended for people in high-risk groups, such as:

  • people who inject drugs or have a sexual partner who injects drugs
  • people who change their sexual partner frequently
  • people travelling to or from a part of the world where hepatitis B is widespread

Pregnant women are also screened for hepatitis B, and if they are infected their baby can be vaccinated shortly after birth to prevent them from also becoming infected.

Who is affected?

Hepatitis B is largely confined to certain groups such as drug users, men who have sex with men and certain ethnic communities (such as South Asian, African and Chinese).

In contrast, hepatitis B is common in other parts of the world, particularly East Asia and sub-Saharan Africa. The World Health Organization estimates that hepatitis B is responsible for 600,000 deaths a year worldwide.


The vast majority of people infected with hepatitis B are able to fight off the virus and fully recover from the infection within a couple of months. The infection can be unpleasant to live with, but usually causes no lasting harm.

But for the small minority of people who go on to develop cirrhosis of the liver, and in some cases liver cancer, the outlook is poor.

Therefore it's important to get yourself vaccinated if you fall into one of the high-risk groups for catching hepatitis B.

Hepatitis B symptoms

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 onto others.

If there are any symptoms, they will develop on average 60-90 days after exposure to the virus.

Common symptoms

Symptoms of hepatitis B include:

  • flu-like symptoms, such as tiredness, general aches and pains, headaches and a high temperature of or above 38C (100.4F)
  • loss of appetite and weight loss
  • feeling sick
  • being sick
  • diarrhoea
  • pain in your upper right-hand side
  • yellowing of the skin and eyes (jaundice)

Symptoms will usually pass within one-to-three months.

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.

Symptoms of chronic hepatitis B may include:

  • feeling tired all the time (fatigue)
  • loss of appetite
  • feeling sick
  • abdominal pain
  • muscle and joint pains
  • itchy skin

When to seek medical advice

Always make an appointment to see your doctor if you have unusual symptoms that persist for more than a few days.

When to seek immediate medical advice

If you suspect that you have been 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 doctor as soon as possible.

Hepatitis B causes

You can become infected with hepatitis B if you are not immune (resistant) to the virus and you come into contact with the blood or body fluids of an infected person.

Many people with hepatitis B do not know they are infected.

The risk of hepatitis B for tourists is considered to be low. However, this risk will increase with certain activities, such as unprotected sex or receiving medical or dental treatment in a developing country (see below). Therefore, travellers are advised to get vaccinated against hepatitis B before visiting any country where this is a problem.

Exposure to infected blood

You are at risk of catching hepatitis B if you:

  • inject drugs and share needles and other equipment, such as spoons and filters, or you are having a sexual relationship with someone who injects drugs
  • have an open wound, cut or scratch, and come into contact with the blood of someone with hepatitis B
  • have medical or dental treatment in a country where equipment is not sterilised properly
  • work closely with blood (for example, healthcare workers and laboratory technicians are at increased risk of injury when the skin is accidentally punctured by a used needle)
  • have a blood transfusion in a country where blood is not tested for hepatitis B
  • have a tattoo or body piercing in an unsafe, unlicensed place (read more about the
    risks of body piercing
  • share toothbrushes, razors and towels that are contaminated with infected blood

All blood donations in the UK are tested for hepatitis B.

Exposure to infected body fluids

You are at risk of catching hepatitis B if you have sex with an infected person without using a condom.

Generally, your risk increases if you are sexually active and have unprotected sex with several different partners; this includes unprotected anal and oral sex.

Prostitutes (both women and men) also have an increased risk of contracting hepatitis B.

Geographical risks

You also have an increased risk if you (or your sexual partner) grew up, lived or worked in a part of the world where hepatitis B is relatively common.


Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood donation is volunteering to give some of your blood to help people who need extra blood after or during surgery. The blood is taken from a vein

A blood transfusion involves transferring blood into a person using a tube that goes directly into a vein in the arm.

The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Immunoglobulins (antibodies) are types of proteins in the body that fight off infection.

Sneezing is an involuntary expulsion of air and bacteria from the nose and mouth.

How Hepatitis B is diagnosed

Hepatitis B is diagnosed by a

blood test
that shows a positive reaction to hepatitis B surface antigen (the outer surface of the hepatitis B virus that triggers a response from your immune system). A positive result means that your body is making antibodies to try and fight the hepatitis B virus.

Your doctor may also request a liver function test. This is a blood test that measures certain enzymes and proteins in your bloodstream, which indicates whether your liver is damaged. These will often show raised levels if you are infected with the hepatitis B virus.

Treating hepatitis B

If you are diagnosed with hepatitis B, it is likely that your doctor will refer to you a specialist, usually a hepatologist (a liver specialist).

Most people tend to be free of symptoms and recover completely within a couple of months, never going on to develop chronic (long-term) hepatitis.

There is usually no specific treatment for acute (short-term) hepatitis B. Unless your symptoms are particularly severe, you should be able to manage them at home.

You can take over-the-counter painkillers such as

and may be prescribed codeine if pain is more severe. Nausea (feeling sick) can often be controlled with a medication called metoclopramide.

If you are diagnosed as having a hepatitis B infection, you will be advised to have regular blood tests and physical check-ups.

Once your symptoms get better you will need further testing to check that you are free of the virus and have not developed chronic hepatitis B.

Chronic hepatitis B

If you have chronic hepatitis B, you will be symptom-free for much of the time.

However, you may need to take medication, possibly for many years, to prevent liver damage. You may also need regular tests to assess the state of your liver. This might include blood tests, an ultrasound and possibly a liver biopsy. This is to assess whether the virus is currently damaging the liver and how much damage has been done.


The main treatment for chronic hepatitis B is antiviral medication, which helps stop the hepatitis B virus from causing liver damage.

Most patients do not require treatment, as although the virus is present in the body, it does not always damage the liver. In some patients, their immune system suppresses the virus without causing damage. However if there is evidence of ongoing liver damage then treatment is required.

There are now very effective medications that can suppress the virus over many years and this can slow down the damage that is being done to the liver, allowing the body to repair this. However, it is unusual for this treatment to clear the virus permanently.

It is very important that you take your treatment as prescribed, even if you feel well or are finding side effects troublesome, as stopping treatment early can lead to drug resistance and could also lead to liver damage. Always speak to your doctor before you come off these drugs.

The two main types of antivirals are described below. You may require a combination of these.

Nucleoside analogs

Nucleoside analogs are a type of antiviral medicine that prevent the genetic code of the virus from being copied into healthy cells.

The two most commonly used nucleoside analogs in this country are called tenofovir and entecavir.

They have the advantage that serious side effects are rare.


Tenofovir is available in tablet form which should usually be taken with food.

Side effects of tenofovir include:

  • diarrhoea
  • feeling sick
  • being sick
  • skin rash
  • feeling weak
  • dizziness
  • in rare cases, kidney problems


Entecavir is available in liquid form. The medication will also come with a special measurement spoon you can use to measure out your dose.

Side effects of entecavir include:

  • being sick
  • feeling sick
  • insomnia
  • dizziness

If you feel dizzy, avoid driving or using tools or machinery.

Lactic acidosis and nucleoside analogs

A rare but serious side effect that can occur with all types of nucleoside analogs is that the medication can cause a build-up of lactic acid in your blood. This is known as lactic acidosis and is potentially serious if left untreated.

Initial warning signs and symptoms of lactic acidosis include:

  • feeling very weak or tired
  • having unusual muscle pain
  • breathing difficulties
  • having stomach pain along with feeling or being sick
  • feeling usually cold, especially in your arms and legs
  • feeling dizzy or light-headed
  • having a fast or irregular heartbeat

If you experience any of these warning signs and symptoms, contact the doctor in charge of your care for advice.

Pegulated Interferon alfa

Pegulated Interferon alfa can be used in the treatment of hepatitis B where there are very high levels of the virus. It stimulates the immune system (the body’s defence against infection) to attack the hepatitis B virus.

The medication is usually given by injection once a week over four-to-six months.

It's common to experience flu-like symptoms, such as a high temperature and muscle and joint pain, after beginning to take pegulated interferon alfa. Taking paracetamol can often help relieve these side effects and they should get better with time.

However, in some people pegulated interferon alfa can cause a wide range of persistent and unpleasant side effects. This means that treatment needs to be withdrawn and an alternative antiviral will need to be used.

If you start to feel any uncomfortable side effects of interferon alfa, tell your doctor.

Regular monitoring

If you have chronic hepatitis B, the state of your liver will need to be regularly monitored via

blood tests
to see how well you are responding to treatment.

Other tests may include an

ultrasound scan
– which is used to check for any abnormalities on the surface of your liver

The frequency of these other tests may depend on the results of your blood tests.

Preventing the spread of hepatitis B

While the medications mentioned above can slow the spread of chronic hepatitis B and hopefully prevent complications such as cirrhosis, they cannot cure the infection. This means you can still pass hepatitis B on to other people.

You should avoid having unprotected sex with someone, including anal and oral sex, unless you are sure they are immunised against hepatitis B.

If you are an injecting drug user, never share your needles with other drug users.

You should also take some sensible precautions to avoid the spread of infection, such not sharing toothbrushes or razors with other people.

Complications of hepatitis B

Without treatment, about a third of people with chronic hepatitis B infection go on to develop a disease of the liver, which can be very serious.

It is estimated that 15%–25% of people with untreated chronic hepatitis B die of liver disease.


Scarring of the liver (

) affects around one-in-five people with chronic hepatitis C, often many years after they first contracted the infection.

Cirrhosis doesn't usually cause any noticeable symptoms until extensive damage to the liver has occurred. It can then trigger symptoms such as:

  • tiredness and weakness
  • loss of appetite
  • weight loss
  • feeling sick
  • very itchy skin
  • tenderness or pain around the liver

If you do develop cirrhosis, it is important to prevent it getting worse by avoiding drinking any alcohol, which has a damaging effect on the liver.

While there are range of treatments that can sometimes relieve some of the symptoms of cirrhosis, the only hope of a complete cure is a

liver transplant

Read more about the

treatment of cirrhosis

Liver cancer

Around 1 in 10 people with cirrhosis caused by chronic hepatitis B will go on to develop

liver cancer

Symptoms of liver cancer include:

  • unexplained weight loss
  • being sick
  • feeling sick
  • jaundice

Read more about the

treatment of liver cancer

Fulminant hepatitis B

An uncommon and serious complication of acute hepatitis B is known as fulminant hepatitis B, where the immune system attacks the liver and causes extensive damage to it. Fulminant hepatitis B occurs in around 1 in 100 adults with chronic hepatitis B (it is much rarer in children).

It can lead to symptoms such as:

  • mental confusion
  • swelling of the abdomen due to a build-up of fluid
  • jaundice

This complication is a medical emergency and 7 out of 10 people will die from it.

Chronic Chronic usually means a condition that continues for a long time or keeps coming back. Liver The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.