Abstract
Neisseria meningitidis is differentiated into 12 distinct serogroups, of which A, B, C, W-135, X, and Y are medically most important and represent an important health problem in different parts of the world. The epidemiology of N. meningitidis is unpredictable over time and across geographic regions. Recent epidemiological surveillance has indicated an increase of serogroup Y invasive meningococcal disease in some parts of Europe as shown in the epidemiological data for 2010 from various European countries previously published in this journal. ( 1) Here, data is reported indicating that the emergence of serogroup Y continued in 2011 in various regions of Europe. The average age of persons affected by N. meningitidis serogroup Y seems to have decreased in some countries in comparison to the previous decade.