Hib is an term for a bacteria (a kind of germ) called Haemophilus influenzae type b. Before 1992, Hib was the most common cause of bacterial meningitis. Hib also caused many other serious infections: bacteremia, pneumonia, epiglottitis (a life-threatening infection of the airway above the voice-box), skin, and joint infections. Most cases of Hib meningitis and other Hib infections occurred in children less than 5 years of age. The highest rate of Hib disease was in infants 6 to 18 months of age. Now all forms of Hib disease, including meningitis, is extremely rare in Canada and all other countries which routinely immunize infants with the Hib vaccine.
Meningitis is the most common form of illness in those infected with Hib. Meningitis caused by Hib has the same symptoms as meningitis caused by other bacteria. Without treatment, all patients with Hib meningitis die. Even with modern treatment with antibiotics, Hib meningitis caused death in about 1 in 20 cases and long-term problems such as deafness and brain damage in 1 out of 10 to 20 survivors.
Hib infection is spread through close contact with secretions (saliva or mucous) from the nose or throat of an infected person. Prolonged close contact is necessary to become infected. Spread of Hib is generally similar to that of meningococcal and pneumococcal disease. Most people who carry Hib bacteria do not become ill. The major factor which determines immunity to disease is the presence or absence of antibody against the specific polysaccharide (a complex sugar) which makes up the outermost coat or capsule of the type b strain.
Since 1992, Hib vaccination has been recommended for all infants in Canada at 2, 4, 6 and 18 months of age. Since then the frequency of Hib meningitis and all other forms of Hib disease has decreased by more than 98%. For more information on Hib vaccines, go to Meningitis Vaccines.