Which disease is prevented by vaccination against Haemophilus influenzae type b?

• A. Meningococcal meningitis
• B. Haemophilus influenzae meningitis
• C. Viral meningitis
• D. Pneumococcal pneumonia

Answer: (B)

Vaccination against Haemophilus influenzae type b protects against invasive Hib disease, most notably Hib meningitis. Before the Hib vaccine, Hib meningitis was a leading cause of bacterial meningitis in young children, so the vaccine specifically targets the bacteria that cause this meningitis. By teaching the immune system to recognize Hib, it prevents the bacteria from invading the central nervous system.

Meningococcal meningitis is caused by Neisseria meningitidis and is prevented by vaccines targeting that organism, not Hib. Viral meningitis is caused by viruses and isn’t prevented by Hib vaccination. Pneumococcal pneumonia is caused by Streptococcus pneumoniae, for which a pneumococcal vaccine exists; it is not prevented by Hib vaccination.