Updated: January 29, 2007
Haemophilus influenzae type b (Hib) is a bacterium that can infect the outer lining of the brain causing meningitis. Hib is transmitted from person to person through mucus droplets that are spread by coughing or sneezing. Invasive Hib disease occurs most often at three months to three years of age, peaking at six to seven months of age. The disease is uncommon after age five years.
Hib can cause a wide variety of serious infections, including pneumonia, severe throat swelling that makes breathing difficult (epiglottitis), and infections of blood, bones, joints, and the covering of the heart. Complications of Hib meningitis include blindness, deafness, mental retardation, learning disabilities, and death. About 5% of children (500 out of every 10,000) with Hib meningitis die despite antibiotic treatment.
The Hib vaccine is available as:
Product: ActHIB® (Hib)
Manufacturer: Aventis Pasteur
Year Licensed: 1993
Product: HibTITER® (Hib)
Manufacturer: Wyeth Lederle
Year Licensed: 1990
Product: PedvaxHIB® (Hib)
Year Licensed: 1989
Product: Comvax® (HBV-Hib)
Year Licensed: 1996
For information on the thimerosal content in these vaccines, see:
The first Hib vaccine was licensed in 1985. Scientists later reformulated the vaccine so that it would be effective in children under 18 months of age, and the FDA licensed this improved version in 1987. The currently used Hib vaccine protects infants as young as six weeks old.
Prior to universal Hib immunization, Hib was the most common cause of bacterial meningitis in infants and preschool-age children, and caused approximately 20,000 cases of invasive disease annually.
Who should receive the vaccine?
Unimmunized children are at increased risk of developing Hib when they are:
Who should not receive the vaccine?
This vaccine is recommended by:
The complete childhood immunization schedule can be found at:
Children should get the Hib vaccine at 2, 4, 6*, and a booster at 12 to 15 months of age.
*Depending on which Hib vaccine is used, a child may not need the dose at six months of age. The doctor or nurse will know whether or not this dose is needed.
Hib is one of only two vaccines that are more effective at providing immunity than natural infection is—the other is tetanus vaccine. Although the Hib vaccine prevents only one form of meningitis, it has nearly eliminated what was once the most common cause of bacterial meningitis in infants and children in the United States. Since Hib vaccines were introduced, the incidence of invasive Hib disease in infants and children in the U.S. has decreased by 99%.
Healthy recipients of Hib vaccine may be susceptible to Hib disease for one to two weeks until antibodies are developed.
Children at increased risk for Hib because of severe combined immunodeficiency syndrome or IgG2 deficiency, and some children with severe immune deficiency from HIV infection or who are receiving chemotherapy for malignant neoplasms (growths), may not develop protective antibodies from the vaccine and may, or may not, benefit from additional doses.
Approximately 25% of children who receive the Hib vaccine experience mild side effects such as pain, redness, or swelling at the site of the shot, while more serious reactions are infrequent.
Studies have shown that children who receive the Hib vaccine in combination with or at the same time as the DTaP vaccine are no more likely to experience side effects than children who receive only the DTaP vaccine.
Questions about the relationship between diabetes and the Hib vaccine have surfaced. Scientific evidence has not supported a relationship. The rate of diabetes in vaccinated children has been compared with the rate in unvaccinated children who were born before the vaccine was available.
No association between the vaccine and the development of diabetes was found.
Please see the following for further information: