Engerix B

How does it work?

Engerix B is a hepatitis B vaccine that contains an inactivated extract of the hepatitis B virus. The vaccine works by provoking the body's immune response, without causing the disease.

When the body is exposed to foreign organisms, such as bacteria and viruses, the immune system produces antibodies against them. Antibodies help the body recognise and kill the foreign organisms. They then remain in the body to help protect the body against future infections with the same organism. This is known as active immunity.

The immune system produces different antibodies for each foreign organism it encounters. This establishes a pool of antibodies that helps protect the body from various different diseases.

Vaccines contain extracts or inactivated forms of bacteria or viruses that cause disease. These altered forms of the organisms stimulate the immune system to produce antibodies against them, but don't actually cause disease themselves. The antibodies produced remain in the body so that if the organism is encountered naturally, the immune system can recognise it and attack it, thus preventing it from causing disease.

Each bacteria or virus stimulates the immune system to produce a specific type of antibody. This means that different vaccines are needed to prevent different diseases.

Engerix B contains an inactivated extract of the virus that causes hepatitis B. It stimulates the immune system to produce antibodies against the hepatitis B virus and thus is given to prevent hepatitis B.

The vaccine is usually given by injection into the muscle (of the upper arm for adults and children, of the thigh for babies and infants). People who are at risk of bleeding following an intramuscular injection, for example people with haemophilia or low numbers of platelets in their blood (thrombocytopenia), may be adminstered the vaccine under the skin. At least three doses are needed and it can take up to six months for the body to form adequate numbers of antibodies to provide immunity against the disease.

One of two schedules can be used to administer the vaccine. Either the first two doses are given a month apart and the third six months after the first dose, or the first three doses are given a month apart, followed by a fourth dose 12 months after the first dose. A booster dose is then recommended five years after the primary course in some vaccination schedules.

This vaccine is not given as a routine vaccine. It is only given to people who are at high risk of contracting hepatitis B. These risk groups include the following: travellers to high risk areas, healthcare workers who have direct contact with blood or body tissues, people such as haemophiliacs who frequently receive blood transfusions or blood products, close contacts of people with hepatitis B, babies born to mothers with hepatitis B, people with chronic kidney failure or chronic liver disease, staff and clients of residential accomodation for the mentally handicapped, workers in mortuaries, prisoners, intravenous drug abusers and their sexual partners and people who frequently change sexual partners.

What is it used for?

Prevention of hepatitis B

Warning!

People who have an underactive immune system, for example due to disease such as HIV infection, dialysis for kidney failure, or treatment with immunosuppressant medicines such as chemotherapy, high-dose corticosteroids, or immunosuppressants used following an organ transplant, may not produce an adequate numbers of antibodies in response to this vaccine. These people may need additional doses of the vaccine if blood tests show their antibody levels are too low.

This vaccine will not prevent infection by other hepatitis viruses, eg hepatitis A or C.

Not to be used in

Sudden feverish illness

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

The safety of this vaccine when given during pregnancy has not been studied. However, as it contains inactivated virus it is not expected to cause any harm to the developing baby. The vaccine should be given with caution during pregnancy, and only if the potential benefits outweigh any risks to the foetus. Seek medical advice from your doctor.

The effect of this vaccine on a breastfeeding child after the mother is given the vaccine have not been studied. However, it is unlikely to cause any harm. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Temporary soreness, redness or hardening of the skin around the injection site

Disturbances of the gut such as diarrhoea, nausea, vomiting or abdominal pain

Headache

Dizziness

Pins and needles sensations (paraesthesia)

Rash or itching

Fatigue

Fever

Cold or flu-like symptoms

Pain in the muscles or joints

Allergic reactions such as skin rash, swelling of the lips, tongue and throat (angioedema) or narrowing of the airways (bronchospasm)

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

This vaccine is not known to affect other medicines.

This vaccine may be given at the same time as other vaccines, but separate injection sites should be used.

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