Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

About Haemophilus influenzae Disease

Haemophilus influenzae (including Hib) is a bacterium that can cause a severe infection, occurring mostly in infants and children younger than five years of age. In spite of its name, Haemophilus influenzae does not cause influenza (the "flu"). It can cause lifelong disability and be deadly.

There are six identifiable types of Haemophilus influenzae bacteria (a through f) and other non-identifiable types (called nontypeable). The one that most people are familiar with is Haemophilus influenzae type b, or Hib. There’s a vaccine that can prevent disease caused by Hib, but not the other types of Haemophilus influenzae.

This photograph depicts the colonial morphology displayed by Gram-negative Haemophilus influenzae bacteria, which was grown on a medium of chocolate agar, for a 24 hour time period, at a temperature of 37°C. See PHIL 12449, for a closer view of these bacterial colonies.
Types of Haemophilus influenzae Infection

Infections caused by Haemophilus influenzae bacteria...

Mother comforting her child.

Lists typical symptoms of certain infections caused by Haemophilus influenzae bacteria…

Senior couple at park.
Risk Factors

Explains who is most at risk for a Haemophilus influenzae infection...

Child in hospital.

Types of severe problems that can occur with a Haemophilus influenzae infection...

Girl sneezing.
Causes and Transmission

Explains more about Haemophilus influenzae bacteria and how they can spread from person-to-person...

Lumbar puncture to collect sample of cerebrospinal fluid.
Diagnosis and Treatment

Explains how various types of Haemophilus influenzae disease are diagnosed and treated...

baby getting vaccinated.

Lists ways to prevent Haemophilus influenzae infection...

Photomicrograph of Haemophilus influenzae as seen using a Gram-stain technique.

Photos of Haemophilus influenzae bacteria and infections, including Hib...

Images and logos on this website which are trademarked/copyrighted or used with permission of the trademark/copyright or logo holder are not in the public domain. These images and logos have been licensed for or used with permission in the materials provided on this website. The materials in the form presented on this website may be used without seeking further permission. Any other use of trademarked/copyrighted images or logos requires permission from the trademark/copyright holder...more

External Web Site Policy This graphic notice means that you are leaving an HHS Web site. For more information, please see the Exit Notification and Disclaimer policy.

Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    TTY: (888) 232-6348
    Contact CDC-INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #