Content Information
Control measures are for Haemophilus influenzae type b (Hib) only. There are no control measures for other types.
A. Isolation and Quarantine Requirements
Current recommendations are as follows:
Period of Isolation of Patient
Isolate the case until 24 hours after initiating appropriate antimicrobial treatment to eliminate carriage. Cefotaxime and ceftriaxone or chloramphenicol is recommended for treatment concurrently or singly until antibiotic sensitivities are known. Rifampin should be given to eliminate nasal carriage of the organism.
Protection of Contacts
Prophylaxis is indicated to protect children less than 12 months old or a child of 1-3 years who is inadequately immunized. If this circumstance is found everyone around them, including household contacts of any age, should receive prophylaxis.
When 2 or more cases of invasive disease have occurred within 60 days and unimmunized or incompletely immunized children attend the child-care facility, administration of rifampin to all attendees and supervisory personnel is indicated. For a single case of Hib disease in a child who attends childcare, the decision to offer chemoprophylaxis to the childcare contacts should be made based on a case by case basis.
B. Protection of Contacts of a Case
Isolate the case
Isolate the case until 24 hours after initiating appropriate antimicrobial treatment. Currently, only the treatment drugs cefotaxime and ceftriaxone are known to eradicate Hib from the nasopharynx. Patient’s who are younger than 2 years of age or have susceptible household contacts, treated with ampicillin or chloramphenicol, must also receive rifampin prophylaxis to eliminate nasal carriage. Also, note that Hib disease does not necessarily confer immunity to subsequent disease. Immunize as follows
-
Children with invasive Hib disease at less than 24 months old - immunize according to the age-appropriate schedule for unvaccinated children and as if they had received no prior doses. Begin 1 month after onset of disease or as soon as possible thereafter. For additional information, please refer to the table below.
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Children with invasive Hib disease at older than 24 months old - no immunization is necessary, regardless of previous immunization status, because the disease probably induced a protective immune response and second episodes at this age are rare.
Antimicrobial prophylaxis for close contacts
Although several antibiotics are useful for treatment of invasive Hib disease and elimination of carriage in the case, rifampin is the appropriate drug to use for antibiotic prophylaxis of contacts. Several studies have shown that rifampin eradicated Hib carriage in greater than or equal to 95% of contacts of primary Hib cases, including children in child cares.
Prophylaxis is needed for all household contacts (including adults) in households with any children less than 12 months old who have not received a primary vaccine series, or a child of 1-3 years who is inadequately immunized, or a household with an immunocompromised child regardless of that child's Hib immunization status.
If the criteria in the above paragraph are met, prophylaxis should be initiated as soon as possible. Most secondary cases in households occur in the first week after hospitalization of the index case. Prophylaxis of household contacts that begins more than or equal to 1 week after hospitalization of the case may still be of benefit, although initiation of prophylaxis beyond 4 weeks after that date is probably of limited utility. It is important for all children and employees having at least four hours of contact with the ill child in the week before onset or hospitalization to take rifampin, unless immunization criteria are met. Prophylaxis is not recommended for pregnant women who are contacts because the effect of rifampin on the fetus has not been established.
|
Age Group |
Dosage/Schedule |
|---|---|
|
Infants < 1 month of age |
10 mg/kg PO QD x 4 days |
|
Children |
20 mg/kg PO QD x 4 days |
|
Adults |
600 mg PO QD x 4 days |
The risk of secondary disease in children attending child-care centers appears to be lower than that observed for age-susceptible household contacts, and secondary disease in child-care contacts is rare when all contacts are older than 2 years. Also, the efficacy of rifampin in preventing disease in child care groups is not established. Nevertheless, rifampin prophylaxis is recommended in certain situations, as indicated in the table below.
Indications and Guidelines for Rifampin Chemoprophylaxis for Contacts of Index Cases of Invasive Haemophilus influenzae Type b (Hib) Disease
Chemoprophylaxis recommended
In certain index cases:
- Index case, if treated with regimens other than cefotaxime or ceftriaxone. Chemoprophylaxis (rifampin) usually is provided just before discharge.
In certain household situations:
- All household contacts (except pregnant women),(1) irrespective of age, in households where at least 1 contact is < 48 months of age and is unimmunized or incompletely immunized(1)
- All household contacts (except pregnant women),(1) irrespective of age, in households where a child is < 12 months of age, even if the primary series has been given
- All household contacts (except pregnant women),(1) irrespective of age, in households with an immunocompromised child, irrespective of the child’s Hib immunization status
In certain child care situations:
- Nursery and child care centers contacts where > 2 cases occurred within 60 days, with > 1 unimmunized or incompletely immunized child < 48 months of age (2,3)
For a single case of Hib disease in a child who attends childcare, the decision to offer chemoprophylaxis to the childcare contacts should be made based on a case by case basis.
Chemoprophylaxis not recommended
In certain individuals:
- Pregnant women
In certain household situations:
- Occupants of households with no children < 48 months of age other than the index patient
- Occupants of households when all household contacts < 48 months of age have completed their Hib immunization series (4)
In certain child care situations:
- Nursery and child care contacts of 1 index case, when all children < 48 months of age have completed their Hib immunization series (4)
- Nursery and child care center contacts where > 2 cases occurred within 60 days, when all children < 48 months of age have completed their Hib immunization series (4)
Footnotes
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Defined as persons residing with the index patient or nonresidents who spent > 4 hours with the index case for > 5 of the 7 days preceding the day of hospital admission of the index case.
-
Only children who are age-appropriately immunized and on rifampin should be permitted to enter the child care group during the time prophylaxis is given. Children enrolling in the child care center or other setting during the time prophylaxis is given should also receive rifampin, as should supervisory personnel.
- When a single case has occurred, the advisability of rifampin prophylaxis in exposed child care groups with unimmunized or incompletely immunized children is controversial, but many experts recommend no prophylaxis.
- Complete immunization is defined as having had > 1 dose of conjugate vaccine at > 15 months of age; 2 doses between 12 and 14 months of age; or a 2- or 3-dose primary series (number of doses required depends on vaccine type and age at initiation) when < 12 months with a booster dose at > 12 months of age. Note that all infants (< 12 months of age) are by definition incompletely immunized.
Ensure appropriate immunization of contacts
The number of doses required is determined by the current age of the child and the number, timing, and type of Hib vaccine doses previously received. Unvaccinated and incompletely vaccinated children less than 5 years old should be scheduled for completion of the recommended age-specific immunization schedule (see definition of “complete immunization” in Footnote 4 of the table above). Infants should be placed on an accelerated schedule using minimum intervals between doses. Unvaccinated high-risk individuals older than 5 years should receive one dose.
The accelerated schedule for situations in which an incompletely vaccinated child has been exposed follows:
| Type of Hib vaccine |
Minimum age for first dose |
Minimum interval from dose 1 to 2 |
Minimum interval from dose 2 to 3 |
Minimum interval from dose 3 to 4 |
|---|---|---|---|---|
| HbOC (HIB-TITER®) |
6 weeks |
1 month |
1 month |
This booster at > 12 mo. of age and > 2 mo.after previous dose |
| PRP-T (ActHIB®, OmniHIB®) |
6 weeks |
1 month |
1 month | This booster at > 12 mo. of age and > 2 mo.after previous dose |
| PRP-OMP (PedVax-HIB®) |
6 weeks |
1 month | This booster at > 12 mo. of age and > 2 mo. after previous dose |
Not required |
Conduct surveillance
Careful observation of exposed contacts, especially children younger than 4 years, is essential. Those in whom a febrile illness develops should receive prompt medical attention, regardless of Hib vaccination status.
D. Preventive Measures
Routine childhood vaccination is the best preventive measure against Hib disease. Good personal hygiene (which consists of proper handwashing, disposal of used tissues, not sharing eating utensils, etc.) is also important.
Please consult the chapter on Haemophilus influenzae in the Red Book of the American Academy of Pediatrics for a full discussion of vaccines, immunization schedules, and special circumstances. For example, children, including those older than 5 years, with underlying conditions predisposing them to Hib disease may need additional doses.
Iowa Dept. of Public Health, Revised 7/15