Meningococcal carriage and vaccination in army recruits in Italy.

The effect of Neisseria meningitidis group A and C polysaccharide vaccine on nasopharyngeal carriage was studied in the training center for army medical officers in Florence. Nasopharyngeal swabs were cultured for N. meningitidis at the time of vaccination (one week after entry to service) and again seven weeks later in a follow-up cohort of 171 men. During the two surveys the overall carriage did not showed significant difference (respectively 16% and 12%); while the percentage of isolates belonging to the serogroup C showed a significant reduction from 6% to 0.6% (P less than 0.01). No increased prevalence of meningococci belonging serogroups other than A or C was observed during the two surveys. The cumulative carriage was 20%. Out of the 35 carriers during the whole study period, only 5 (14%) belonged to the same serogroup. These findings show that meningococcal vaccine may inhibit the nasopharyngeal carriage of group specific meningococci in army recruits.