Acquisition of W135 meningococcal carriage in Hajj pilgrims and transmission to household contacts: prospective study

Abstract

The annual Islamic pilgrimage to Mecca and Medina (Hajj) attracts more than two million pilgrims from all over the world. Overcrowding provides ideal conditions for transmission of meningococci.During the Hajj 2000 an international outbreak of meningococcal disease occurred.1 This outbreak generated particular interest as it was caused by serogroup W135, which hitherto had not played a major role in epidemics. 2 3 Furthermore, many close contacts of asymptomatic returning pilgrims were affected.2 Although vaccination can protect pilgrims against invasive disease due to W135, it does not prevent acquisition of pharyngealcarriage, which is the primary source for transmission.4 Returning pilgrims may spread the bacteria to their unvaccinated household contacts or even to the community at large. We investigated the extent of transmission of Neisseria meningitidis in Hajj pilgrims and their contacts, in order to provide evidence for developing a rationalpublic health policy. We conducted a prospective study of meningococcal carriage in Singaporean pilgrims before the Hajj 2001 and in pilgrims and their household contacts two weeks after …