This is a monovalent vaccine containing the purified capsular polysaccharide of Haemophilus influenzae type b (Hib), a bacterium responsible for severe invasive diseases in young children. The polysaccharide antigen (0.025 mcg) is conjugated to a protein carrier (typically tetanus toxoid or CRM197 in commercial vaccines, though the carrier is not specified in this basic composition) to enhance immunogenicity, particularly in infants. Thiomersal (10 mcg) is included as a preservative to prevent bacterial and fungal contamination in multi-dose vials. This formulation is a critical component of India's Universal Immunization Programme (UIP) and is primarily administered as part of the Pentavalent vaccine (DTP-HepB-Hib).
Adult: Not routinely recommended. For high-risk adults (e.g., asplenia), a single dose may be considered as per specialist advice.
Note: For intramuscular use only. Shake the vial or pre-filled syringe well before use. The preferred site for infants and young children is the anterolateral aspect of the thigh. For older children, the deltoid muscle can be used. Do not administer intravenously, intradermally, or subcutaneously. Use a separate, sterile syringe and needle for each injection.
The Hib capsular polysaccharide (polyribosylribitol phosphate, PRP) is a T-cell independent antigen. Conjugation to a protein carrier (e.g., tetanus toxoid) converts it into a T-cell dependent antigen. This allows for: 1) Enhanced immunogenicity in infants <18 months, 2) Induction of immunological memory (memory B-cells), and 3) A booster response upon re-exposure. The vaccine stimulates B-lymphocytes to produce specific IgG antibodies against the PRP capsule. These antibodies facilitate opsonization and complement-mediated bacteriolysis, preventing invasive Hib disease.
Pregnancy: Category C: Not recommended for routine use in pregnancy. Should only be considered if clearly needed for a pregnant woman with high-risk conditions (e.g., functional asplenia). Risk-benefit must be assessed by a specialist.
Driving: No effect. Side effects like fever or drowsiness may temporarily impair ability.
| Immunosuppressants (e.g., high-dose corticosteroids, chemotherapy, biologics) | Diminished immune response to the vaccine; may not confer adequate protection. | Major |
| Other Vaccines (Live or Inactivated) | Can generally be administered simultaneously at different sites. No clinically significant interference when given as part of a combination vaccine (Pentavalent). | Minor |
Same composition (Haemophilus Influenzae Type B Capsular Polysaccharide (0.025mcg) + Thiomersal (10mcg)), different brands: