Text Size:

Is Hib Contagious?

Is Hib contagious?Yes. H. Influenzae b is spread by airborne droplets or direct contact with secretions or fomites.1

In general, Hib disease is considered to be minimally contagious. It enters the body through the nasopharynx, and can remain there for several months with no symptoms. In some persons the organism causes an invasive infection and develops into meningitis. Although it’s not known how it gets into the bloodstream, it’s possible that a co-existing viral or mycoplasma infection of the upper respiratory tract may be a contributing factor.

Before vaccines were introduced in the U.S., health officials had identified a seasonal pattern to Hib, with a peak during September through December, and a second peak from March through May. For the most part, the contagious potential of Hib is considered to be limited, but close contact with persons who have the disease can lead to outbreaks of the disease. Before the vaccine approximately two-thirds of all cases of Hib affected infants and children under 15 months old.2,3 Hib is a largely age-dependent disease; it is not common beyond the age of 5 years old.4

Hib can spread rather quickly in populations in enclosed quarters, such as families and daycare centers.5

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.

« Return to Hib Table of Contents

« Return to Vaccines & Diseases Table of Contents


1 Kasper DL, Fauci AS, Braunwald E, et al. Harrison’s Principles of Internal Medicine 16th Edition. 2005. pp 864-866.

2 Broome CV. Epidemiology of Haemophilus Influenzae Type b Infections in the United States. Pediatr Infect Dis J. Aug 1987. Vol 6 Issue 8 pp 779-782. Online. (Accessed June 2012)

3 FDA.gov. Haemophilus b Conjugate Vaccine Manufacturer’s Product Insert. Sanofi Pasteur. May 6, 2009. Online. (Accessed June 2012)

4 CDC.gov. Haemophilus Influenzae Type B. The Pink Book. No Date. Online. (Accessed June 2012)

5 Devarajan VR, Cunha BA. Haemophilus Influenzae Infections. Medscape. Jan. 10, 2012. Online. (Accessed June 2012)

Make a Difference

NVIC is 100% funded by donations. Please give. Help educate families about preventing vaccine injury and death by donating to NVIC today.

Ask Questions
Vaccine doses banner