Haemophilus influenzae Type b (Hib) Infection

For more information about Hib disease in general, see:

For information on Hib vaccine 

  • Guidelines for prevention of transmission

    FROM: Red Book: 2010 Report of the Committee on Infectious Diseases. 28th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2010: 314-321.


  • Report the case to Epidemiology & Assessment within one (1) working day
    • Phone:  714-834-8180
    • Fax:  714-834-8196
  • Place case in respiratory (droplet) isolation until 24 hours after start of appropriate antimicrobial therapy
  • If case was treated with a regimen other than cefotaxime or ceftriaxone (e.g., treated with meropenem, ampicillin, or chloramphenicol), give rifampin (see dosage below) to case just before discharge from the hospital to eradicate Hib colonization, IF;
    • case is younger than 2 years of age, OR
    • case has a susceptible household contact (see definition below).
  • If the case received treatment with ceftriaxone or cefotaxime, rifampin is NOT necessary.
  • Note:  Children younger than 24 months of age with Hib invasive infection can remain at risk of developing a second episode of disease. These children should be immunized starting 1 month after onset of disease, or as soon as possible thereafter, according to the age-appropriate schedule for unimmunized children and as if they had received no previous Hib vaccine doses. See 2010 Red Book p. 321, 319, and 35.

Household contacts

For this situation, household contacts are defined as people residing with the case or who spent 4 or more hours with the case for at least 5 of the 7 days preceding days preceding the day of hospital admission for the case.

  • Give rifampin (see dosage below) to ALL non-pregnant household contacts if the household has ANYsusceptible contacts, defined as the following:      
    1. a child under age 12 months who has not received the primary series, OR
    2. a child younger than 4 years of age who is unimmunized or incompletely immunized* (defined below), OR
    3. an immunocompromised child (regardless of immunization status).
  • Prophylaxis should be initiated as soon as possible. If household contacts are unable to fill prescriptions or you are unable to contact them, refer contacts to Epidemiology & Assessment at 714-834-8180 as soon as possible.
  • Vaccinate children who are unimmunized or incompletely immunized* (defined below) for Hib
  • Inform household that any exposed child who develops a febrile illness should be evaluated by a physician as soon as possible.

*Complete immunization is defined as:

  • at least 1 dose of conjugate vaccine at 15 months of age or older
  • 2 doses between 12 and 14 months of age
  • a 2- or 3- dose primary series when younger than 12 months with a booster dose at 12 months of age or older. NOTE: the primary series for Hib is 2 doses for the PRP-OMP (Merck) Hib-containing vaccines [PedvaxHIB® (monovalent Hib vaccine) and COMVAX® (Hib/hepatitis B)] and 3 doses for the PRP-T (Sanofi Pasteur) Hib-containing vaccines [ActHIB® (monovalent Hib vaccine), Pentacel® (DTaP/IPV/Hib) and TriHIBit® (DTaP/Hib)]. Primary series for Hib started with the PRP-OMP (Merck) vaccines and completed with the PRP-T (Sanofi Pasteur) vaccines should include 3 doses.

Day care, nursery school, or child care center contacts

  • Chemoprophylaxis with rifampin (see below for dosage) should be considered for all day care, nursery school, or child care center attendees and child care providers when 2 or more cases of invasive disease have occurred in the facility within 60 days and unimmunized or incompletely immunized* (see above) children attend the child care facility. Please refer any child care exposures as soon as possible to Epidemiology & Assessment at 714-834-8180 for follow-up.
  • Unimmunized or incompletely immunized* (see above) children should receive a dose of vaccine if age-appropriate and should be scheduled for completion of the recommended age-specific immunization schedule.


Chemoprophylaxis with rifampin


  • Infant less than 1 month old: dosage not established; some experts recommend 10 mg/kg once daily for 4 days
  • Infants ≥ 1 month of age and Children: 20 mg/kg once daily to maximum of 600 mg daily for 4 days
  • Adults:  600 mg daily for 4 days

** Rifampin is not recommended for pregnant women or persons with liver disease. Instruct patients that rifampin can stain soft contact lenses, turn urine orange, and interfere with oral contraceptives during current cycle.