Carriage of serogroup W-135, ET-37 meningococci in The Gambia: implications for immunisation policy?
MacLennan JM., Urwin R., Obaro S., Griffiths D., Greenwood B., Maiden MC.
We found high levels of symptomless carriage of a hyperinvasive Neisseria meningitidis strain (electrophoretic type 37 [ET-37], serogroup W-135) during a vaccine trial in Gambian children in 1996. Serogroup C, ET-37 complex meningococci cause 30-40% of meningococcal disease in countries such as the UK, and have a point prevalence of 0.5-1.0%. The recent Haj-associated spread of serogroup W-135, ET-37 complex meningococci, which has been accompanied by numerous secondary cases, might be explained by the apparently raised carriage rates reported here.