Engerix B - product overview
Engerix B is a vaccine used to prevent hepatitis B, which is an infectious illness of the liver caused by a virus.
Some people have the hepatitis B virus in their body but cannot get rid of it. They can still infect other people and are known as carriers. Carriers can spread the virus to others who come into contact with their body fluids, including blood, saliva, semen and vaginal fluids all of which can contain the virus. It is therefore possible to catch the virus from a carrier through, for example, unprotected sex, shared injection needles, treatment using medical equipment which has not been properly sterilised, or through activities such as tattooing or pedicures with equipment that has not been properly sterilised. Another possible transmission route of the virus is a pregnant carrier of hepatitis B passing the virus to her baby at birth.
The main signs of the illness include headache, fever, sickness and jaundice (yellowing of the skin and eyes), but in about three out of ten patients there are no signs of illness. In those infected with hepatitis B one out of ten adults and up to nine out of ten babies will become carriers of the virus, often with no obvious signs of disease initially, although they are likely to go on to develop serious liver damage and in some cases cancer of the liver later in life.
Engerix B contains a part of the outer coat of the hepatitis B virus. This 'outer coating' is not infectious and cannot give you hepatitis B.
When the vaccine is given the body will make antibodies (the body's natural defence system) against the hepatitis B virus. This will protect the individual from infection with hepatitis B should they come into contact with it. This vaccine will not, however, protect the individual from the effects of hepatitis B if they are already infected with the virus, nor will it protect them against other types of liver infection.
Since hepatitis D cannot occur in the absence of hepatitis B infection, Engerix B can also protect against infection with hepatitis D.
No vaccine is totally effective in all individuals who are vaccinated. A number of factors, for example older age, gender, being overweight, smoking and some long term diseases, have been observed to reduce the immune response to hepatitis B vaccines. If they apply to the person who is to have the vaccine, the doctor or nurse may decide to do blood tests or give that person an additional dose of vaccine to ensure protection.
How Engerix B is given
Engerix B is injected into the muscle of the upper arm in adults and children. In babies and young children, it is normally injected into the thigh muscle. However, this vaccine may be injected under the skin for patients with blood disorders.
Adults and children 16 years of age and over are given the 20 μg/1ml vaccine and new-born babies and children 15 years of age and under are usually given the 10 μg/0.5ml vaccine. However, the 20 μg/1ml vaccine may be given to children aged 11-15 years of age if it is thought unlikely that the child will receive the third injection in the vaccination schedule. This will provide a higher level of protection than two doses of the 10 μg/0.5ml vaccine.
The person who is to have the vaccine may receive it at the same time as another vaccine, but the vaccines should always be given at different injection sites. The person receiving the vaccine will need to have a series of injections of Engerix B . Once a course of injections have been completed it will offer long term protection against hepatitis B.
Your doctor or nurse will choose the most appropriate schedule for your circumstances.
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