Haemophilus influenzae type b vaccine targets which serotype?

Haemophilus influenzae type b vaccine targets which serotype?

• A. Serotype b
• B. Serotype a
• C. Serotype c
• D. Serotype d

Answer: (A)

The vaccine is designed against the capsule of Haemophilus influenzae type b. This bacterium has several capsule types, but the type b capsule (polyribosylribitol phosphate, PRP) is the one most associated with invasive disease in children. The Hib vaccine is a conjugate that links the PRP capsule to a protein carrier to provoke a strong, T‑dependent immune response in infancy, providing protection against serious Hib infections like meningitis and epiglottitis. It does not target non-encapsulated strains or other serotypes that lack the type b capsule.

The vaccine is designed against the capsule of Haemophilus influenzae type b. This bacterium has several capsule types, but the type b capsule (polyribosylribitol phosphate, PRP) is the one most associated with invasive disease in children. The Hib vaccine is a conjugate that links the PRP capsule to a protein carrier to provoke a strong, T‑dependent immune response in infancy, providing protection against serious Hib infections like meningitis and epiglottitis. It does not target non-encapsulated strains or other serotypes that lack the type b capsule.