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Secondary Haemophilus influenzae type b in day-care facilities. Risk factors and prevention
Insights
Secondary Haemophilus influenzae type b disease spread in day-care centers is linked to age and hours spent in care. Rifampin prophylaxis effectively prevented secondary cases in close contacts.
Area of Science:
- Pediatric Infectious Diseases
- Epidemiology
- Public Health
Background:
- Haemophilus influenzae type b (Hib) can cause serious secondary infections in day-care settings.
- Understanding transmission dynamics is crucial for prevention strategies.
Purpose of the Study:
- To identify risk factors for secondary Hib disease acquisition in day-care attendees.
- To evaluate the effectiveness of rifampin prophylaxis in preventing secondary Hib infections.
Main Methods:
- A cohort study was conducted across multiple locations (Seattle-King County, Atlanta, Oklahoma).
- Identified primary Hib cases in children under 5 attending day-care.
- Tracked secondary cases within the same classroom and center, analyzing age and attendance duration as risk factors.
Main Results:
- 8% of primary Hib cases resulted in secondary infections within the same classroom.
- Secondary disease risk was highest in infants (0-11 months) and decreased with age.
- Increased hours per week in day-care correlated with higher transmission risk.
- Rifampin prophylaxis demonstrated high efficacy (47%-100%) in preventing secondary Hib cases.
Conclusions:
- Day-care attendance, particularly for younger children and longer durations, increases the risk of secondary Hib disease.
- Rifampin is an effective chemoprophylactic agent for preventing Hib spread in day-care settings.
Abstract:
The risk factors for acquisition of secondary day-care-associated Haemophilus influenzae type b disease were evaluated in a cohort of children in Seattle-King County, Washington; Atlanta; and the state of Oklahoma. During the study period, 129 primary cases were identified in children less than 5 years old who attended day-care facilities. In ten instances (8%), a secondary case occurred between one and 60 days after a primary case in the same classroom. Risk of secondary disease in classroom contacts was strongly age related: 2.4% in children 0 to 11 months old, 1.2% in children 12 to 23 months old, and 0.0% in children 24 to 59 months old. Controlling for age, children attending day-care more hours per week were more likely to transmit or acquire secondary disease. Risk of secondary disease for children in other classrooms at a center where a case had occurred was not significantly greater than risk of primary disease. Administration of rifampin to classroom contacts of a child with invasive H influenzae was effective in preventing secondary cases (95% confidence interval for rifampin efficacy, 47% to 100%). For children 0 to 23 months old not treated with rifampin, risk of secondary disease was 2.7% (95% confidence interval, 1.1% to 4.3%), a risk approaching that reported in household contacts.