What is hepatitis B?
Hepatitis B is a viral infection of the liver, which follows a very
variable course. The hepatitis B virus (HBV) can cause an acute illness
that resolves itself quickly without causing long-term liver damage.
However, in about 20% of cases it causes a chronic illness that lasts
more than six months, sometimes for life, with symptoms that come and
go. In 15-40% of those with chronic infection cirrhosis, liver cancer or
liver failure develop, and so the infection may eventually be fatal.
Hepatitis
B is not very common in the UK, with new infections occurring in about 7
out of every 100,000 of the population every year, usually in adults.
Worldwide, however, it is a major health problem. In Asia and most of
Africa, most people pick up the infection around the time of birth or
during childhood. As a result, two billion people worldwide are infected
with hepatitis B, with 350 million suffering from chronic HBV
infection. It is the 10th leading cause of death worldwide.
The
virus is usually transmitted through contact with infected blood or
body fluids. Only a tiny amount of blood is needed to transmit the virus
because it's so infectious. The hepatitis B virus may also be present
in saliva, vaginal secretions, breast milk and other bodily fluids.
In
the UK, infection commonly occurs through unprotected sexual
intercourse, the sharing of contaminated needles by drugs users,
accidental injury with a contaminated needle (if needles used for
tattooing, body piercing or acupuncture are contaminated) and sharing
razors.
In countries where screening of blood products isn't
routine, or where medical equipment isn't adequately sterilised,
hepatitis B may be transmitted during medical treatment.
Many
people contract hepatitis B while on holiday, especially in countries
where it is very prevalent, when unprotected sex, experimenting with
drugs and accidents needing medical treatment are far more likely.
Hepatitis B symptoms
The incubation period of the hepatitis B virus before symptoms develop is between six weeks and six months.
In
the acute phase symptoms vary. Roughly one-third of cases have no
symptoms - this is called a silent or subclinical infection, or
sometimes anicteric infection, meaning there is no jaundice or yellow
appearance of the skin and membranes. In another third of cases, the
infection causes mild symptoms similar to those of a flu-like illness,
with weakness, aches, headache, fever, loss of appetite, diarrhoea,
jaundice, nausea and vomiting.
In the final third of cases, the
acute phase of infection can cause severe illness that last many months.
In addition to the flu-like symptoms, there's abdominal pain, diarrhoea
and jaundice.
Jaundice occurs in hepatitis infections because the
liver becomes unable to remove a substance called bilirubin from the
blood. This is a pigment that builds up in the body, causing the skin
and whites of the eyes to turn yellow.
Rarely, rapid liver failure develops, which may need a life-saving liver transplant.
In
as many as one in five cases, the infection then goes into a chronic
phase, where people may be apparently healthy with no symptoms but
carrying and shedding the virus (known as healthy carriers).
Alternatively, they may develop a chronic active hepatitis, with similar
symptoms to the acute phase of the infection and also fatigue, poor
appetite, nausea and abdominal discomfort.
Hepatitis B causes
In the UK, the people most at risk of contracting hepatitis B are
injecting drug users, people who have unprotected sex with different
partners, close family members of someone with the infection, babies
born to infected mothers and travellers to high-risk countries who come
into contact with infected blood and other bodily fluids.
Hepatitis B is considered an occupational hazard for healthcare workers, the police and the emergency services.
Preventing hepatitis B
Practising safe sex by using condoms and not sharing needles when
using drugs can reduce the risk of infection. The same advice applies
when travelling.
When having any body piercing, tattoo or
acupuncture, make sure the business is registered with the local
authority, that the needles used are disposable and that an autoclave is
used for any equipment that's sterilised. If the proprietor cannot
confirm these, go elsewhere.
Normal social contact carries no risk
of infection. You can't catch hepatitis B from toilet seats or by
touching an infected person. Clothing with the virus is thought to be
killed by a normal hot wash in a washing machine, and by washing-up
liquid and hot water for plates and cutlery.
Hepatitis B vaccine
There's an effective vaccination to protect people from hepatitis B
infection. It's available from your GP or high street travel centres,
who will advise you whether you need it.
Family and other
household members of an infected person should be vaccinated against
hepatitis B. Healthcare workers, the police, the emergency services and
anyone who is likely to come in contact with infected blood through
their job should also be vaccinated.
Hepatitis B treatments
The majority of people with hepatitis B don't need specific
treatment other than rest, and they eventually make a full recovery.
However, it is important that the infection is monitored to check
whether chronic disease develops, and the person is given advice about
the risk of passing the infection on.
If the infection lasts more
than six months (chronic hepatitis infection, where the virus continues
to actively reproduce in the body) you may need more specific drug
treatment to reduce the risk of permanent liver damage (cirrhosis) and
liver cancer. Your GP should refer you to a specialist in either liver
disease (a hepatologist) or general digestive diseases (a
gastroenterologist). They may recommend treatment either with treatment
called interferon, or with antiviral drugs.
Interferon (either
alpha interferon or longer lasting pegylated interferon) is given as
regular injections and helps boost the immune system to fight the
infection. The response to interferon is variable, and some people who
initially get better get worse again when the treatment is stopped.
Others find that the side effects of interferon mean that they cannot
continue with treatment.
Several different antiviral drugs, known
as nucleoside analogues, are also now used to treat chronic hepatitis.
They aren't a cure, but they do suppress the virus. These drugs may also
have side effects - although not usually so severe as with interferon -
and the virus may become resistant to them.
Occasionally, when there is severe damage to the liver, a liver transplant is recommended.
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