Acute Epiglottitis and Infant Conjugate Haemophilus influenzae Type b Vaccination in Northern Finland

OBJECTIVE: To determine the incidence and characteristics of acute epiglottitis among children (< or = 19 years of age) and adults (> or = 20 years of age) before and after widespread conjugate Haemophilus influenzae type b vaccination for infants. DESIGN: A retrospective population-based survey over a 27-year period from 1967 through 1993 in 35 communities in a northern province of Finland with a population of approximately 300,000. SETTING: An academic tertiary referral center. MAIN OUTCOME MEASURES: All acute epiglottitis cases in the area identified from the hospital discharge register and the regional autopsy register. RESULTS: The average incidence rate for children was 1.8 cases per 100,000 individuals per year (95% confidence interval [CI], 1.3 to 2.5). As no vaccine failures emerged, the incidence rate for children aged 0 to 4 years declined sharply once the vaccination started in 1986 from 7.6 (95% CI, 5.3 to 10.4) to 0 (95% CI, 0 to 3.3) cases per 100,000 individuals per year. By contrast, a fourfold increase in adult acute epiglottitis (incidence rate ratio, 4.6; 95% CI, 2.7 to 7.9) was detected after vaccination of the children, the average incidence rate for the whole period being 1.0 cases per 100,000 individuals per year (95% CI, 0.8 to 1.3). No marked change in the adult patient profile was found during this increase, however. CONCLUSION: Acute epiglottitis practically vanished among young children in this population after conjugate H influenzae vaccination, but adult cases increased, the patient profile remaining the same.