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.