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Haemophilus influenzae type B meningitis: a contagious disease of children
Insights
Young children exposed to Haemophilus influenzae type B meningitis face a high risk of secondary invasive disease. The secondary attack rate in children under five was 2.3%, significantly higher than the endemic rate.
Area of Science:
- Pediatrics
- Infectious Diseases
- Epidemiology
Background:
- Haemophilus influenzae type B (Hib) meningitis is a serious infection.
- Understanding secondary disease transmission within households is crucial for public health.
Purpose of the Study:
- To determine the risk of secondary invasive Hib disease among household contacts of patients with Hib meningitis.
- To calculate the secondary attack rate in close contacts, particularly young children.
Main Methods:
- Surveyed 120 families of 126 consecutive Hib meningitis patients.
- Identified 555 household contacts, with 31% under 5 years old.
- Defined and identified secondary cases based on laboratory confirmation within 30 days of the index case's hospital admission.
Main Results:
- Identified four secondary cases of invasive Hib disease, all in children under 5 years old.
- Calculated a secondary attack rate of 2.3% for children under 5 years, which is approximately 800 times the endemic rate.
- Noted that this is a conservative estimate, with five additional contact cases documented but not included in the rate.
Conclusions:
- Young household contacts, especially those under 5 years, are at a significantly elevated risk of developing life-threatening secondary invasive Hib disease.
- Public health interventions should focus on protecting vulnerable young contacts of Hib meningitis cases.
Abstract:
The families of 126 consecutive patients with Haemophilus influenzae type B meningitis were surveyed for secondary invasive H influenzae disease among household contacts. A total of 120 of the families were contacted. In six cases no contact was possible and the medical record was reviewed. Some 555 household contacts were found; 31% (171) were under 5 years of age. A secondary case was defined as a household contact with H influenzae type B isolated from blood or cerebrospinal fluid more than 24 hours, but less than 30 days, after admission to hospital of the index case. Four secondary cases were identified, all in children aged under 5 years. The secondary attack rate in children under 5 years or less in the month after exposure to an index case was thus 2.3%, 800 times the endemic attack rate for H influenzae meningitis. This is a conservative estimate since five additional contact cases were documented, but not included in the secondary attack rate. Young contacts of a child with H influenzae meningitis are thus at significant risk of life-threatening secondary disease.