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Haemophilus Influenzae Type B (HIB)

What is meningitis?
Meningitis is an infection of the fluid surrounding a person's spinal cord and brain. Common symptoms include a high fever, headache, and a stiff neck. Nausea, vomiting, and sleepiness are also possible. In infants, common symptoms may be difficult to notice. The baby may only appear inactive, irritable, or refuse to eat. As the disease progresses, seizures sometimes occur.(1)

Meningitis can be caused by a virus or bacterium. Viral meningitis is fairly common, usually less severe, and dissipates without treatment.(2,3) Bacterial meningitis can be serious, and may cause hearing loss, learning disabilities, and other neurological damage, including death in a small percentage of cases when treatment is delayed.(4) The disease is diagnosed by performing a spinal tap -- by inserting a needle into the lower back to obtain fluid from the spinal canal. Once proper identification of the responsible bacteria has been determined, antibiotics can be administered.(5)

Bacterial meningitis can be caused by three different types of bacteria: 1) Haemophilus influenzae type b (Hib); 2) Streptococcus pneumoniae; and 3) Neisseria meningitidis (Figure 1). Some forms are contagious, and are spread through coughing and kissing. However, bacterial meningitis is not spread by casual contact or by simply breathing the air where an infected person has been. It is not as communicable as ailments like the common cold or flu.(6)

What is Haemophilus influenzae type b?
Haemophilus influenzae type b, or Hib (no relation to the flu), is a serious bacterial infection that can cause meningitis, pneumonia, swelling of the throat, and other disease complications. Hib is spread through sneezing, coughing, and secretions from an infected person. Treatment mainly consists of intravenously administered antibiotics. Oxygen therapy and other medical tactics may also be required.

Is Hib a common disease? During the 1970s and 1980s, there were an estimated 16,000 to 20,000 Hib infections per year in the United States.(7,8) (Official statistics were not kept, so these figures may have been inflated when the vaccine was being developed.) Meningitis occurred in about half of the cases.(9) Around 25 percent of all Hib infections caused hearing loss, neurological problems, or pneumonia.(10-12) Epiglottitis (inflammation of the throat) accounted for nearly 15 percent of cases.(13) The mortality rate was about four percent.(14,15)

Hib infections occurred at a much lower rate during the 1940s and 1950s. In fact, Hib rates jumped 400 percent between 1946 and 1986.(16-18) Rates tumbled beginning in the 1990s, with just 329 cases of Hib in American children under five years of age in 1994, 259 cases in 1995, and 144 cases in 1996 and 1997 combined.(19-21)

What caused Hib rates to dramatically increase?
Several factors indicate that mass immunization campaigns with pertussis and other non-Hib vaccines may have been responsible for the unprecedented epidemics of invasive bacterial infections, such as Hib, during the 1970s and 1980s. Let's look at some of the evidence:

The most complete, up-to-date information on the Hib vaccine
may be found in the book: Vaccine Safety Manual
