Haemophilus influenzae type b (Hib) is a bacteria that can cause many serious childhood infections, including:
- meningitis - an infection of the fluid surrounding the brain and spinal cord
- pneumonia - a lung infection
- epiglottitis - a severe throat infection
- sepsis - a blood infection
- cellulitis - a skin infection
- suppurative arthritis - a bacterial infection of the joints
- endocarditis - an infection of the valves of the heart
- osteomyelitis - a bone infection
Interestingly, Hib has nothing to do with flu, but got its name because it was once thought to be responsible for an influenza epidemic.
Hib is most common in young children under five years of age and is usually spread by respiratory secretions.
Hib Complications
Before routine use of the Hib vaccine began in 1988, about 20,000 children had Hib infections each year, including 12,000 cases of bacterial meningitis. In fact, Hib was once the most common cause of bacterial meningitis in kids.
Pre-vaccine, complications could be severe, affected about 30% of kids, and included deafness, seizures, blindness, and mental retardation. And about 5% of children with bacterial meningitis that was caused by the Hib bacteria died.
Hib Symptoms
The symptoms of Hib infections depends on the type of infection the child has. For example, a young child with Hib meningitis will likely have a high fever, headache, irritability, vomiting, and won't be eating well.
In epiglottitis, the child will have a high fever and trouble breathing and swallowing. Typically, children with epiglottitis sit upright and lean forward to breath easier, drool, and have stridor, a high-pitched breathing sound.
Hib Outbreaks
The Hib vaccine did a good job of preventing almost all Hib infections in the United States -- at least until recent years.
Five children under age five years of age developed Hib infections in Minnesota in 2008, resulting in one death.
Another five children have had Hib infections in Pennsylvania since October 2008, resulting in two deaths. According to the American Academy of Pediatrics, "All of these cases were in unvaccinated or under-vaccinated children. One of the children, an unvaccinated 4-year-old child whose family belongs to a religious community that eschews medical care, died of bacterial meningitis due to Hib in March 2009."
Hib Vaccine
Even with the Hib vaccine shortage and the recommendation for temporary deferral of the booster dose of Hib at 12 through 15 months, it is very important that all children finish the primary series of Hib vaccine when they are two, four, and six months old.
Older children should follow the catch-up schedule for the primary series of Hib vaccine.
Sources:
CDC Health Advisory. Invasive Haemophilus influenzae Type B Disease in Young Children and Importance for All Young Children to Receive 3 Dose Primary Series with Available Hib-containing Vaccine. Wednesday, March 18, 2009.
Gershon: Krugman's Infectious Diseases of Children, 11th ed.
MMWR. Invasive Haemophilus influenzae Type B Disease in Five Young Children --- Minnesota, 2008. January 30, 2009 / 58(03), 58-60.
