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Since 1992-93 vaccination against Haemophilus influenzae type b (Hib) has been included in the general Swedish childhood vaccination programme. The aim of the present study is to describe the epidemiology, identify and describe vaccine failures and calculate vaccine effectiveness during the first 6 y after introduction of vaccination against Hib. Laboratory reports of blood and cerebrospinal isolates to the Swedish Institute for Infectious Disease Control were used as the source for identifying the patients. Additional information was subsequently obtained from physicians and parents of children who had developed the disease during the study period. Vaccine failures were identified and vaccine effectiveness calculated. During the study period, 152 cases of invasive H. influenzae were identified in the age group 0-14 y. During the 6-y period, 6 true vaccine failures, 6 apparent vaccine failures and 1 possible vaccine failure were found in nearly two million vaccinated child-years. The effectiveness of the Hib vaccination in the birth cohort of children 1993 to 1997 in Sweden was calculated to be 96.1% (95% confidence interval 94.2-97.5). The study supports earlier studies from several countries that conjugated Hib vaccination introduced in general childhood vaccination programs is effective and substantially decreases suffering from invasive Hib diseases.

Over a period of 18 years 219 consecutive cases of acute epiglottitis were diagnosed and subsequently investigated in order to elucidate the aetiology, epidemiology and outcome of this disease in a well-defined population in Sweden before general vaccination against Haemophilus influenzae type b infection was introduced. Compared with the results from other parts of the industrialized world, high incidence rates were found in both children (14/100,000/year) and adults (2.3/100,000/year). The annual trend showed a significant decline in incidence among children, whereas in adults it remained unchanged. In cases where the aetiological agent could be determined, infection with H. influenzae type b was the main cause of disease in all age groups. However, in adults 27% (6/22) had a disease caused by micro-organisms other than H. influenzae type b that were verified with a blood culture. Sixty-eight per cent had a negative blood culture. The mortality rate was 0.5% (1/219) and 6% (13/219) developed a significant complication of the disease.

Objectives:We studied the incidence and bacterial epidemiology of acute epiglottitis presenting in the first 16 years following the introduction of general childhood vaccination against Haemophilus influenzae type b. Our main objectives were to analyse (1) the incidence of Streptococcus pneumoniae epiglottitis in adults and (2) the distribution of pneumococcal serotypes involved.Materials and methods:The medical records of patients with acute epiglottitis (International Classification of Disease code J05.1) were investigated. Streptococcus pneumoniae serotyping was performed using gel precipitation.Results:The overall incidence of acute epiglottitis was 0.98 cases/100 000/year, compared with 4.5 cases/100 000/year before the vaccination programme. The incidence was reduced both in children and adults, compared with pre-vaccination values. However, the incidence of Streptococcus pneumoniae epiglottitis in adults increased from 0.1 to 0.28 cases/100 000/year over the same time period. The causative agent was Streptococcus pneumoniae in 10 adults. Nine of 10 pneumococcal strains could be serotyped. All but one serotype is represented in the 23-valent pneumococcal polysaccharide vaccine (PPV23) used in adults.Conclusion:In acute epiglottitis, now a disease of adults, the most important bacterial aetiology is Streptococcus pneumoniae. The serotype distribution found in this study indicates that the infection is preventable by PPV-23 vaccination with the 23-valent polysaccharide vaccine. [ABSTRACT FROM PUBLISHER]