Invasive Meningococcal Capsular Group Y Disease, England

Enhanced national surveillance for invasive meningococcal disease in England and Wales identifi ed an increase in laboratory-confi rmed capsular group Y (MenY) disease from 34 cases in 2007 to 44 in 2008 and 65 in 2009. For cases diagnosed in 2009, patient median age at disease onset was 60 years; 39 % of patients had underlying medical conditions, and 19 % died. MenY isolates causing invasive disease during 2007–2009 belonged mainly to 1 of 4 clonal complexes (cc), cc23 (56 % of isolates), cc174 (21%), cc167 (11%), and cc22 (8%). The 2009 increase resulted primarily from sequence type 1655 (cc23) (22 cases in 2009, compared with 4 cases each in 2007 and 2008). cc23 was associated with lpxL1 mutations and meningitis in younger age groups (<25 years); cc174 was associated with nonmeningitis, particularly pneumonia, in older age groups (>65 years). The increase in MenY disease requires careful epidemiologic and molecular monitoring. Invasive meningococcal disease is associated with substantial rates of illness and death worldwide (1), with most infections caused by 5 capsular groups, namely A, B, C, W135, and Y (2). In the United Kingdom, where capsular group C (MenC) conjugate vaccines have been routinely used since 1999 (3,4), capsular group B (MenB) causes>80 % of confirmed cases, particularly among infants and adolescents (5). Invasive infections caused by other capsular groups are infrequent and sporadic (6,7)