Engerix B
Hepatitis B Vaccine (rby)
Information for the Medical, Nursing and Pharmaceutical Professions
Presentation
'Engerix B' is a Suspension of hepatitis B surface antigen produced by yeast cells using a recombinant DNA technique. It is available as a fine white suspension in the following presentations: adult vials (1 ml) (UK and Ireland): paediatric vials (0.5 ml) (UK only); adult prefilled syringes (1 ml) (UK only). Each 1 ml contains 20 micrograms of protein, comprising at least 95% hepatitis B surface antigen, adsorbed on aluminium hydroxide adjuvant, together with thiomersal 1:20,000 as preservative.
Uses
Active immunisation against infection caused by hepatitis B virus.
Preference should be given to those at increased risk of infection, primarily those likely to be exposed to blood, blood products or other body fluids (see Further information). In addition, those who live in or travel to high endemic hepatitis B areas such as Africa or the Far East and their close contacts are at a generally increased risk of infection, and should be considered for vaccination. 'Engerix B' may be used as a booster in patients previously immunised with other hepatitis B vaccines.
Dosage and administration
'Engerix B' is for intramuscular use only, and must not be given intravenously or intradermally. Prior to vaccination, the vaccine should be well shaken and be visually inspected for any colour variations or particulate matter. Once shaken, the vaccine is slightly opaque.
'Engerix B' must not be mixed in the same syringe or injected at the same site as other vaccines. The immunisation regimen consists of three doses of vaccine, the second dose at one month and the third at six months after the initial dose. Where more rapid immunisation is required, for example with travellers, the third dose may be given at two months after the initial dose, with a booster dose at 12 months. Specific humoral antibodies against the surface antigen of hepatitis B appear in almost 100% of those who have received three doses.
Adults and children over 12 years: 20 micrograms (1 ml) given intramuscularly.
Neonates and children 12 years and under: 10 micrograms (0.5 ml) given intramuscularly. The vaccine should be administered in the deltoid region, though the antero-lateral thigh is the preferred site for infants. 'Engerix B' should not be administered in the buttock since this may result in a lower immune response. In patients with severe bleeding tendencies such as haemophiliacs, subcutaneous injection may be considered. In neonates born to HBsAg positive mothers, hepatitis B immunoglobulin should be given simultaneously with the vaccine at different sites within a few hours of birth. For other subjects at particular risk, similar simultaneous administration may be considered. Users in the Republic of Ireland should see current Irish Data Sheet for recommendations on concomitant immunoglobulin administration.
Contra-indications, warnings, etc.
Contra-indications: Hypersensitivity to any component of the vaccine. Severe febrile infections.
Precautions: In patients having renal dialysis, or those who are immunocompromised, response may be impaired and further vaccinations may be necessary. (Users in the Republic of Ireland should refer to the current Data Sheet.)
Because of the prolonged incubation period of hepatitis B, infection may be present at the time of the vaccination. If so, Engerix may be ineffective.
As with all vaccinations a solution of 1:1000 adrenaline should be available for injection should an anaphylactic reaction occur.
Use in pregnancy: No studies in pregnant animals have been done. Engerix B is not recommended in pregnancy unless there is a definate risk of hepatitis B.
Adverse reactions: These are usually mild. The most common reactions, occurring in up to half of vaccinees are mild transient local soreness, erythema and induration at the injection site.
Less common systemic complaints, not necessarily related to vaccine, include low-grade fever, malaise, fatigue, arthralgia, arthritis, myalgia, headache, dizziness, syncope, nausea, vomiting, diarrhoea, abdominal pain, lymphadenopathy, abnormal liver function tests, and rashes, rarely including urticaria. Severe skin disorders such as erythema multifonne have exceptionally occurred.
Very rarely: transient artliralgia, pruritus and urticaria have been reported appearing one week or more after injection.
Neurological manifestations occurring in temporal association have been reported with the vaccine and include very rarely paraesthesia and extremely rarely paralysis, neuropathy and neuritis including Guillain-Barre syndrome, optic neuritis and multiple sclerosis. No causal relationship has been established.
Early onset allergic-type reactions have been reported rarely.
Pharmaceutical precautions
'Engerix B' should be stored between 2C and 8C, its shelf life then being three years, and must not be frozen. It should not be diluted. Protect from light.
Legal category
POM.