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 (jaundice)
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
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.
In England, 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.
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 (cirrhosis), which can take 20 years to develop, and around 1 in 10 people with cirrhosis will develop liver cancer.
There is currently no specific treatment for acute hepatitis B, other than using painkillers to relieve symptoms.
Chronic hepatitis B can be treated using a combination of antiviral medications designed to slow the spread of the virus and prevent damage to the liver.
Read more about the treatment of hepatitis B.
There is a vaccine that is thought to be 95% effective in preventing hepatitis B. Due to the relative rarity of hepatitis B in England, the vaccine is not given as part of the routine childhood vaccination schedule.
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.
Read more about hepatitis B vaccination.
Who is affected?
Hepatitis B is uncommon in England and cases are largely confined to certain groups such as drug users, men who have sex with men and certain ethnic communities (South Asian, African and Chinese). There were 2,697 newly reported cases in England during 2010.
In contrast, hepatitis B is common in other parts of the world, particularly China, central and south-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.