Acquisition of meningococcal serogroup W-135 carriage in Turkish Hajj pilgrims who had received the quadrivalent meningococcal polysaccharide vaccine.

Invasive meningococcal disease is a recognized public health problem worldwide, with a dynamic and changeable epidemiology. In Turkey, the second most common pathogenic meningococcal serogroup (after serogroup B) is W-135, including an epidemic in 2005, which has been strongly associated with Hajj pilgrims and their close contacts. In two studies conducted in 2010, we assessed meningococcal carriage in intending Turkish pilgrims to the Hajj when they attended to receive a plain polysaccharide vaccine against serogroups A, C, W-135, and Y and, upon their return, to determine the acquisition of meningococcal carriage by the pilgrims themselves and subsequently their household contacts. Nasopharyngeal swabs were obtained from pilgrims before the Hajj and upon their return. Swabs were then obtained from 39 household contacts of pilgrims who were shown to have acquired carriage during the Hajj. Of the 472 pilgrims before the Hajj, 63 (13%) were positive for meningococcal carriage, of which 52 cases (83%) were serogroup W-135. In the 296 pilgrims tested after the Hajj, 81 (27%) were positive for meningococcal carriage, including 74 (91%) with W-135. In 11 family members of pilgrims who acquired W-135 carriage at the Hajj, 10 (91%) had acquired carriage of serogroup W-135. This study illustrates the acquisition of meningococcal carriage, predominantly of serogroup W-135 by pilgrims attending the Hajj, and the transmission of this carriage to their family members on their return, explaining the source of W-135 meningococcal disease in Turkey.