What is meningococcal Y or meningococcal W disease?
There are several groups of meningococcal bacteria (A,B,C,W135,Y and Z). In the past 50 years, most meningococcal disease in the UK and Ireland has been due to MenB and MenC, while other groups have dominated in other parts of the world.
Why is this important?
This information is important because it helps us to understand the patterns of disease we observe and investigate the potential usefulness of new ACWY vaccines in the UK.
A meningococcal conjugate vaccine that protects against groups A, C, W and Y was licensed in Europe early in 2010. Although it is unclear how this vaccine will be used in the UK except as a travel vaccine, a rise in group Y or W disease could make it much more useful as routine vaccine, which could be used in place of the MenC vaccine in the childhood immunisation schedule. Alternatively it may be used in adolescence to boost immunity to meningococcal C and provide protection against meningococcal Y, W (and serogroup A which causes epidemic meningitis in Africa).
Although there are currently few cases of meningitis and septicaemia due to groups Y and W in the UK, disease due to these bacteria is more common in other countries and cases could potentially increase. In the US, the proportion of meningococcal cases caused by serogroup Y increased from 2% at the beginning of the 1990s to 37% at the end of that decade. Although still rare here, Group Y disease is rising as is carriage of the bacteria (see poster
from Dr C. Bayliss at MRF conference). Group W is normally not a major cause of disease in the UK, but caused outbreaks here and around the world, associated with the Hajj pilgrimage to Mecca in 2000 and 2001.