Haemophilus influenzae type b (Hib) Disease Fact Sheet

What is Haemophilus influenzae type b (Hib)?

Haemophilus influenzae type b (Hib) is a bacterium that can cause serious infections, especially in young children. Before Hib vaccines became available, Hib was one of the most common causes of bacterial meningitis in children in the United States. Hib can cause meningitis (inflammation of the lining of the brain and spinal cord) as well as pneumonia (lung infection), bloodstream infections, ear infections, skin infections, and joint infections.

Transmission

Hib is spread from person-to-person by airborne droplets and direct contact with infected respiratory secretions.

Hib is carried in the nose or throat of children and adults who are infected. It is possible for people who are not ill to carry Hib and spread it to others. It is then spread to the next person through contact with discharge or droplets from the nose or mouth.

Signs and Symptoms

The time period between when someone is exposed to Hib and when symptoms develop is unknown but may be as short as 2 to 4 days. Symptoms may include:

Fever
Stiff neck
Drowsiness
Nausea and vomiting
Headache
Symptoms at site of infection (for example: skin or joint redness, tenderness, or swollen area)

Risk Factors

People at increased risk for Hib disease include:

Children younger than 5 years of age, especially infants
People who are unimmunized or incompletely vaccinated
Persons with weakened immune systems
People without a functioning spleen or with certain underlying medical conditions
Elderly adults with chronic health conditions

Treatment
Early diagnosis and treatment are very important. Seek medical attention promptly if symptoms of Hib disease develop. Treatment with antibiotics should be started immediately to stop the infection from causing serious complications or death. Certain close contacts of someone diagnosed with Hib disease may also need preventive antibiotics, especially in childcare or household settings. High-risk contacts can include:

Children 4 years of age and younger who are unimmunized or incompletely immunized
Children younger than 12 months who have not completed their primary Hib vaccine series
Immunocompromised children regardless of vaccination status

Steps You Can Take to Protect Yourself

Vaccination is the best way to prevent Hib disease. The Hib vaccine is recommended for all children starting at 2, 4, 6 and 15 months of age. Hib vaccine is recommended for all children under 5 years of age who have not been previously immunized, and others may need Hib vaccine if they are at an increased risk for disease.