Carriage of Neisseria meningitidis in Europe: a review of studies undertaken in the region.

Meningococcal conjugate vaccines induce herd protection by preventing nasopharyngeal meningococcal acquisition, which is a prerequisite for invasive disease. Thus, meningococcal carriage epidemiology is important in understanding relationships between carriage and disease. A literature search traced information on meningococcal carriage in 27 EU countries. Meningococcal carriage prevalence differed within and between countries, varying across age groups, serogroup distribution and over time. Carriage prevalence increased during childhood, peaking in 15-24-year-olds. While serogroup B was usually the dominant serogroupable carried serogroup, serogroups C, W-135 and Y were also frequently carried. Current carriage studies in Europe are limited. New studies using standardized methods are needed to improve our understanding of meningococcal disease etiology and transmission, and to monitor the impact of meningococcal conjugate vaccines in populations.