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The epidemiology of acute epiglottitis in children in Western Australia
Insights
Haemophilus influenzae type b caused 71% of epiglottitis cases in Western Australian children. A proposed surveillance system aims to track the impact of Haemophilus influenzae type b immunization.
Area of Science:
- Pediatrics
- Infectious Diseases
- Public Health Surveillance
Background:
- Epiglottitis is a serious upper airway infection primarily affecting young children.
- Haemophilus influenzae type b (Hib) was a leading cause of bacterial meningitis and epiglottitis before widespread vaccination.
- Understanding the epidemiology of Hib epiglottitis is crucial for public health interventions.
Purpose of the Study:
- To determine the incidence and microbiological causes of epiglottitis in children under 15 in Western Australia.
- To evaluate the sensitivity of different case definitions for invasive Hib disease in detecting epiglottitis cases.
- To propose a surveillance system for monitoring the impact of Hib immunization.
Main Methods:
- A comprehensive case definition was applied to all epiglottitis cases in children under 15 in Western Australia over a 5-year period.
- Microbiological analysis was performed to identify causative agents, particularly Haemophilus influenzae type b.
- Incidence rates were calculated and compared with data from other regions.
Main Results:
- Haemophilus influenzae type b was identified in 71% of 103 epiglottitis cases.
- The majority of cases (75%) occurred in children under 5 years of age.
- The estimated annual incidence in this age group (13.5/100,000) was lower than in Victoria (22.7/100,000).
- Even a sensitive Canadian surveillance definition for invasive Hib disease would have missed 35% of epiglottitis cases.
Conclusions:
- Haemophilus influenzae type b remains a significant cause of epiglottitis in unvaccinated or under-vaccinated populations.
- Existing surveillance definitions for invasive Hib disease may underestimate the true burden of epiglottitis.
- A tailored, sensitive surveillance system is needed to effectively monitor Hib immunization program impact in Western Australia.
Abstract:
A comprehensive case definition was used to study all cases of epiglottitis that occurred in children under 15 years of age in Western Australia during a 5 year period. There was microbiological evidence of Haemophilus influenzae type b infection in 71% of 103 cases of epiglottitis. Seventy-five per cent of cases occurred in children under 5 years of age. In this age group, the estimated annual incidence (13.5 episodes per 100,000) was significantly lower than that reported in Victoria (22.7 per 100,000). The case definition of invasive H. influenzae type b disease used for surveillance purposes in Canada was more sensitive than the definitions used in the United States or England and Wales, yet even the Canadian definition could have detected only 65% of the cases of epiglottitis that occurred in Western Australia. A simple and sensitive surveillance system which could be used to monitor the impact of H. influenzae type b immunization in Western Australia is proposed.