Haemophilus influenzae type b

  • What invasive disease is caused by Haemophilus influenzae type b?

    The most common types of invasive disease caused by Hib are meningitis, epiglottitis, pneumonia, arthritis, and cellulitis.1

    Other, less common types of infection caused by Hib include osteomyelitis (bone infection) and pericarditis (infection of the sac covering the heart).1

  • What is the microbiology of Haemophilus influenzae type b?

    Hib is an encapsulated strain of bacteria that colonizes the human nose and throat. The bacteria may spread throughout the body through the bloodstream, and may become life threatening.1

    A polysaccharide, polyribosylribitol phosphate, or PRP, composes the outer layer of the Hib bacterium, and is an important determinant in the disease virulence.1

  • How is Haemophilus influenzae type b transmitted?

    Hib bacteria are thought to be spread primarily through contact with respiratory droplets expelled from an infected person. Although the contagious potential of Hib is thought to be limited, close contact with case-patients (eg, childcare, household, or institutional setting) can also lead to disease transmission.1

  • What is the pathology of Haemophilus influenzae type b?

    The bacteria enter through the nasopharynx, where they begin to colonize. The bacteria may remain there for several months without symptoms. In some people, the bacteria cause invasive Hib disease.1

  • What are the clinical manifestations and symptoms associated with Haemophilus influenzae type b?

    The most common clinical manifestation of serious Hib disease is meningitis. Prior to widespread vaccine use, approximately 50% to 65% of all meningitis cases were attributed to the Hib strain.1

    Meningitis often presents with high fever, headache, and stiff neck. Less frequently, hearing impairment or other neurologic sequelae can result.1

Disease Information

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CDC Information

CDC=Centers for Disease Control and Prevention.

Hib=Haemophilus influenzae type b.

VACC-1137021-0001 01/17
1. Centers for Disease Control and Prevention (CDC). Haemophilus influenzae type b. In: Hamborsky J, Kroger A, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Washington, DC: Public Health Foundation; 2015:119–134. http://www.cdc.gov/vaccines/pubs/pinkbook/index.html. Accessed October 27, 2016.