Indications
Hepatitis B surface antigen (HBsAg), made by recombinant technology, is the active part of hepatitis B vaccines. It is used to protect against infection with the hepatitis B virus, which can cause liver inflammation, cirrhosis and liver cancer. It is given on its own, or as part of combination childhood vaccines (pentavalent or hexavalent) that also protect against diphtheria, tetanus, whooping cough, Haemophilus influenzae type b and, in some, polio.
How It Works
The surface antigen is a harmless protein from the outer coat of the virus, produced in yeast cells. It contains no live virus and cannot cause hepatitis B. When injected, it trains the immune system to make antibodies against the virus, so the body can fight off a real infection later.
Dosage and Administration
The vaccine is given as an injection into a muscle (usually the thigh in babies and the upper arm in older children and adults) by a doctor, nurse or trained vaccinator. The number of doses and timing follow the national immunisation schedule or the doctor’s advice; babies usually receive it within the combination vaccine series in the first months of life. Adults at risk receive a separate course, as prescribed.
Interactions
- Can usually be given at the same visit as other routine vaccines, at a different injection site.
- Medicines that weaken the immune system, such as high-dose steroids, chemotherapy or transplant medicines, may reduce the response.
- Hepatitis B immunoglobulin may be given at the same time at a separate site for babies of infected mothers.
Contraindications
- Severe allergic reaction to a previous dose or to any vaccine ingredient, including yeast.
- For combination vaccines containing whooping cough: brain disease (encephalopathy) within 7 days after a previous dose.
- Vaccination is postponed during a moderate or severe illness with high fever; a minor cold is not a reason to delay.
Side Effects
Common reactions include pain, redness or swelling at the injection site, mild fever, irritability or crying in babies, tiredness, loss of appetite and headache. These usually settle within one to two days.
Get urgent medical help if, after vaccination, there is difficulty breathing, swelling of the face or throat, fainting, a fit (seizure), very high fever, or a baby who is unusually floppy, pale or unresponsive, or cries inconsolably for hours.
Pregnancy and Lactation
The hepatitis B vaccine contains no live virus and may be given during pregnancy and breastfeeding when protection is needed, on a doctor’s advice. Combination childhood vaccines are not meant for adults.
Precautions and Warnings
- Tell the vaccinator about bleeding disorders, allergies, previous vaccine reactions or a weak immune system.
- People with weak immunity or on dialysis may need extra doses and antibody checks.
- Wait at the clinic for 15 to 30 minutes after vaccination.
Overdose
Overdose is very unlikely because vaccines are given by health professionals in fixed doses. Extra doses are generally not harmful.
Therapeutic Class
Vaccine (recombinant hepatitis B antigen), alone or in combination vaccines.
Storage
Store in a refrigerator at 2 to 8°C, do not freeze. Freezing destroys the vaccine. Protect from light.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.