Haemophilus Influenzae Type B

What it is and how it works

The vaccine contains purified Hib capsular polysaccharide (polyribosylribitol phosphate, PRP) covalently conjugated to a carrier protein such as tetanus toxoid. Conjugation converts the T-cell-independent polysaccharide into a T-cell-dependent antigen, inducing protective anti-PRP antibodies and immunological memory even in infants.

Indications

Active immunisation against invasive disease caused by Haemophilus influenzae type b (e.g. meningitis, epiglottitis, pneumonia, septicaemia) in infants and young children, and in older children and adults at increased risk such as those with asplenia or splenic dysfunction.

Dosage and administration (summary)

0.5 mL by intramuscular injection (anterolateral thigh in infants, deltoid in older children and adults), with the number of doses and schedule according to the national immunisation programme.

Contraindications

Hypersensitivity to any component of the vaccine, including tetanus toxoid, or a severe reaction to a previous dose; postpone in acute severe febrile illness.

Warnings and precautions

Appropriate treatment for anaphylaxis must be available. The vaccine protects only against type b strains and does not replace routine tetanus immunisation; immunosuppressed patients may have a reduced response, and caution is needed in thrombocytopenia or bleeding disorders because of intramuscular injection.

Pregnancy

Not routinely indicated in pregnancy; may be given when there is a clear risk of Hib infection.

Storage and supply

Store refrigerated at 2–8 °C; do not freeze; protect from light.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.