The epidemiology of Haemophilus influenzae type b disease in the Republic of Ireland.

A 2-year case-control study was conducted to describe the epidemiology of Haemophilus influenzae type b (Hib) and investigate Hib disease risk factors in the Republic of Ireland. Between October 1991 and September 1993. 149 laboratory confirmed incident cases were matched with community controls. Annual Hib disease incidence was 25.4 per 100,000 children under 5 years, with peak incidence (65.8 per 100,000) in the 6-11 months age-group. Meningitis was the predominant clincial condition. Twenty-four (16.1%) isolates were resistant to ampicillin. Crèche or day-care attendance and the presence of chronic illness emerged as risk factors for Hib disease. Empirical first line treatment for suspected Hib infection warrants alternatives to ampicillin such as cefotaxime. Completed immunization with Hib conjugate vaccine by 6 months of age is required for maximum disease prevention. Until all children are receiving Hib vaccine on schedule, those who are crèche or day-care attendees and those with chronic illness should be prioritized for timely immunization.