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Absence of increasing incidence of meningitis caused by Haemophilus influenza type b
Abstract:
An epidemiologic survey of meningitis caused by Haemophilus influenzae type b in children aged zero to four years during an 11-year period (January 1965-December 1975) was conducted in the Baltimore, Maryland, metropolitan area to examine recent trends in the incidence of this disease. Cases of H. influenzae meningitis were identified at all 19 hospitals in the city and county of Baltimore and all 41 hospitals in the surrounding area. The population at risk (age, zero to four years) was estimated using yearly birth rates provided by the state of Maryland and U.S. Census information for 1960 and 1970. Yearly age-adjusted incidence was calculated; in contrast to previous studies, there was no significant increase in the annual incidence (range, 12-27; mean, 19.3/100,000 population at risk). Previous reports of recent increases in the incidence of meningitis caused by H. influenzae type b may be due to differences in study techniques.
Insights
This study found no significant increase in Haemophilus influenzae type b meningitis incidence in young children in Baltimore from 1965-1975. Findings suggest previous reports of rising rates may stem from differing study methods.
Area of Science:
- Epidemiology
- Pediatrics
- Infectious Diseases
Background:
- Haemophilus influenzae type b (Hib) meningitis is a significant cause of childhood illness.
- Previous studies suggested an increasing incidence of Hib meningitis.
Purpose of the Study:
- To investigate trends in the incidence of Haemophilus influenzae type b meningitis in children aged 0-4 years.
- To examine recent changes in Hib meningitis rates over an 11-year period.
Main Methods:
- Conducted an 11-year epidemiologic survey (1965-1975) in the Baltimore metropolitan area.
- Identified all cases of Hib meningitis across 60 hospitals.
- Estimated population at risk using birth rates and U.S. Census data.
Main Results:
- Calculated yearly age-adjusted incidence rates for Hib meningitis.
- Observed no significant increase in annual incidence, with rates ranging from 12-27 per 100,000 population at risk (mean 19.3).
Conclusions:
- The incidence of Haemophilus influenzae type b meningitis remained stable in the studied population.
- Discrepancies with prior studies may be attributed to variations in research methodologies.