In 2018, pilgrims in Turkey were given the meningococcal conjugate vaccination for the first time before leaving for Hajj. The purpose of this study was to see if immunisation has any influence on the prevalence of Neisseria meningitidis carriage among pilgrims returning to Turkey. The N.meningitidis carriage before and after pilgrimage was studied in this prospective paired (departing and arrival) cohort study of pilgrims aged 10–80 years. Oropharyngeal samples were obtained from 229 pilgrims both before and after their journey to Mecca, Kingdom of Saudi Arabia (KSA).
At the time of departure, 3.9 percent of the passengers tested positive for meningococcal carriage; all positive samples were serogroup B. When the pilgrims returned to Turkey, one (0.4 percent) of them tested positive for serogroup B, despite not being a carrier before to the trip. This is the first research to look at meningococcal carriage after a conjugate vaccination is given to Turkish Hajj pilgrims.
Reference: https://www.tandfonline.com/doi/full/10.1080/21645515.2019.1680084