Neisseria meningitidis nasopharyngeal carriage during the Hajj: A cohort study evaluating the need for ciprofloxacin prophylaxis

Background The annual Muslim pilgrimage has the potential of increase risk for acquisition of Neisseria meningitidis. Here, we evaluate the Hajj impact on the prevalence of N. meningitidis carriage in a paired and non-paired cohort of pilgrims. Secondary objectives were to calculate the compliance with recommended vaccination. Methods This is a prospective paired (arriving and departing), non-paired arriving and non-paired departing cohort study with the collection of nasopharyngeal samples at the start and the end of the Hajj. Results The study included unpaired arriving pilgrims at King Abdul Aziz International Airport (N = 1055), unpaired departing cohort (N = 373), and a paired cohort (N = 628) who were tested on arrival and departure. Meningococcal vaccination was received by all pilgrims, 98.2% received quadrivalent polysaccharide vaccine (ACWY), and 1.8% received meningococcal quadrivalent conjugate vaccine (MCV4). Only 1.61% and 23.03% received pneumococcal and influenza vaccines, respectively. Of the 1055 arriving unpaired pilgrim, 36 (3.4%) tested positive for nasopharyngeal carriage of N. meningitidis, and 24 (66.7%) of these were serogroup B, the remainder were non-groupable. Haemophilus influenza was detected among 45 (4.3%), and 11 (1%) carriers were positive for both N. meningitidis and H. influenzae. Out of 373 in the unpaired departing cohort, 6 (1.61%) tested positive for N. meningitidis, and 34 (9.1%) were positive for H. influenzae. Of the 628 paired cohort pilgrims, 36 (5.7%) pilgrims were positive for N. meningitidis at arrival and 16 (2.5%) pilgrims were positive after the hajj. Conclusion This the largest study of the epidemiology of N. meningitidis among pilgrims. The study showed a significant difference in the carriage between pilgrims from high endemicity and other pilgrims with a predominance of serogroup B. The continued use of ciprofloxacin as prophylactic antibiotics should be reconsidered as well as the consideration to add serogroup B as a required vaccination.