Who is at Highest Risk for Getting Hib?
According to the CDC, the most striking feature of Hib is that it is age-dependent and uncommon after the age of 5 years old. Before the vaccine was introduced in the U.S., the age at which most children were stricken with invasive Hib was between 6 and 7 months old, and usually under the age of 2 years.1,2
Risk factors for Hib disease include household crowding, large household size, child care attendance, low socioeconomic status, low parental education levels, and school-aged siblings. Gender is also a factor―males are at a higher risk of getting the disease than females. Also, chances of household contacts of a child who has invasive Hib are about 600 times higher than the risk for the general population.3
Certain population groups have a higher incidence of Hib than others, for example, the incidence of meningitis due to Hib is three to four times higher among black children than among whites. Also, according to Harrison’s Principles of Internal Medicine, the incidence of meningitis caused by invasive Hib is 10 times higher in certain Native American groups than in the general population. Researchers speculate that age of exposure, socioeconomic conditions, and genetic differences may account for the inability to mount an immune response to the bacterium. Epiglottis caused by Hib is different in that it usually occurs in occurs in children ages 2 years through 7 years old. Interestingly, Navajo Indians and Alaskan Eskimos don’t usually get epiglottis.
Cellulitis caused by Hib usually occurs in young children on the head or neck, and sometimes appears bluish-red in color. Most patients with Hib-caused cellulitis also have bacteremia, and 10 percent have an additional infection. Hib can also cause pneumonia in infants that is clinically indistinguishable from other types of bacterial pneumonia.
Household members of a family where a child has Hib should be treated with a prophylaxis dose of oral rifampin if they are under age 4 and not vaccinated for Hib. Children over age 4 and under 12 also should receive a dose.4
IMPORTANT NOTE: NVIC encourages you to become fully informed about Haemophilus Influenza Type B (Hib) and the Hib vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.
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1 CDC.gov. Haemophilus Influenzae Type B. The Pink Book. No Date. Online. (Accessed June 2012)
2 Kasper DL, Fauci AS, Braunwald E, et al. Harrison’s Principles of Internal Medicine 16th Edition. 2005. pp 864-866.
3 CDC.gov. Haemophilus Influenzae Type B. The Pink Book. No Date. Online. (Accessed June 2012)
4 Kasper DL, Fauci AS, Braunwald E, et al. Harrison’s Principles of Internal Medicine 16th Edition. 2005. pp 864-866.