Medical Definition of Haemophilus influenzae type B

Reviewed on 3/29/2021

Haemophilus influenzae type B: Abbreviated as HIB, a bacterium capable of causing a range of diseases including ear infections, cellulitis (soft tissue infection), upper respiratory infections, pneumonia, and such serious invasive infections as meningitis with potential brain damage and epiglottitis with airway obstruction. It spreads by droplet through coughs and sneezing. Half of cases present as meningitis with fever, headache, and stiff neck. The remainder present as cellulitis, arthritis, or sepsis (bloodstream infection). About 5 percent of cases are fatal, Up to 20 percent of the survivors have permanent hearing loss. More than 90 percent of all HIB infections occur in children 5 years of age or younger-the peak attack rate is at 6 to 12 months of age. HIB causes 2 to 3 million cases of disease each year and about 450,000 deaths, the vast majority of them in developing countries today.

The disease can be prevented with the HIB vaccine, which is usually given at 2, 4 and 6 months of age with a final booster is given at 12-15 months of age. HIB vaccine rarely causes severe reactions. The HIB vaccine has almost eradicated the disease in the US and other industrialized countries. Before the vaccine, some 20,000 cases of HIB invasive disease in preschool children were reported every year in the U.S. compared to less than 300 cases after the advent of the vaccine.

The vaccine is a "conjugate" vaccine. It joins ("conjugates") sugars from the HIB bacteria with a protein from another bacteria. The protein stimulates the baby's immature immune cells so they produce antibodies to the HIB sugars, protecting the child from HIB infection.

The prestigious Albert Lasker Award for Clinical Medical Research was given in 1996 to David H. Smith, Porter W. Anderson Jr., John B. Robbins and Rachel Schneerson for their work in developing a vaccine against Haemophilus influenzae type B.



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