Haemophilus influenzae type b disease and vaccination in Europe: lessons learned.

To scrutinize the experiences of those European countries that have played a central role in understanding the behavior of and vaccination for Haemophilus influenzae type b (Hib) diseases, to enlighten weaknesses and to explore whether lessons learned would benefit other countries in combating Hib. Epidemiologic and clinical data on Hib infections and vaccinations were analyzed, including all disease manifestations and all age groups. To improve reliability, sources that used active case finding were especially searched for. In the prevaccination era meningitis represented 40 to 70% of all classical Hib diseases. Epiglottitis was the second most common presentation, except in southern Europe (data not available from former socialist countries). The overall incidence of meningitis and of all Hib disease combined for children ages 0 to 4 years was 23 and 41 per 100000, suggesting 9900 and 17800 cases per year, respectively. Including all age groups and entities, >20000 Hib cases occurred annually. Vaccination, accomplished with two or three primary doses and a late booster, has almost eliminated Hib disease in >10 countries, and >10000 cases per year are prevented. An age analysis of Hib meningitis suggests that strong early immunogenicity is not as imperative in Europe as in some other regions. The incidence of non-type b H. influenzae infections has not increased. With Hib epidemiology comparable with that in Europe, good protection is achieved by various conjugate vaccines also with two primary doses only. However, active research on the whole Hib issue should be a priority, especially in southern and eastern European countries.