Haemophilus influenzae type b is a Gram-negative bacterium that causes meningitis and acute respiratory infections, mainly in children. In both developed and developing countries, it is an important cause of non-epidemic meningitis in young children, and is frequently associated with severe neurological sequelae, even if antibiotics are given promptly. In developing countries, H. influenzae is also a major cause of pneumonia in children. Other important, but less frequent, manifestations of H. influenzae disease include epiglottitis, osteomyelitis, septic arthritis and septicaemia.
Haemophilus influenzae infection is transmitted by droplets from infected (but not necessarily symptomatic) people. Haemophilus influenzae type b be can be prevented by vaccination.
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