Prevalence of Haemophilus influenzae pharyngeal carriers in the school population of Catalonia

The objective of this study was to determine the prevalence of healthy Haem ophilus influenzae (Hi) pharyngeal carriers in a representative sample of t he Catalonian school population, as well as the factors associated. A two-s tage cluster sampling was carried out. Parents were given a questionnaire t o collect information on sociodemographic and epidemiological variables. A pharyngeal swab was performed on children when informed consent was given b y parents, and was cultured on chocolate agar with 260 mu g/ml bacitracin. Of the 1212 children studied, 316 (26%) H. influenzae carriers were detecte d: 5 (0.4%) serotype b, 1 (0.08%) serotype c, 6 (0.5%) serotype e, 5 (0.4%) serotype f, and 299 (24.7%) non-typable. Age, gender and geographical loca tion were the only variables associated with H. influenzae carrier status. The prevalence of non-typable H. influenzae carriers was similar to that of studies carried out in other countries, while that of serotype b carriers was similar to the remainder of H. influenzae capsulates, and lower than th at described in previous studies. These data are in accordance with the low incidence of the disease observed in our context, although the possibility that the vaccine coverage may have affected the results of this study cann ot be dismissed.