A Phase II randomized, observer-blind, placebo-controlled study, to assess efficacy of meningococcal Group B vaccine rMenB+OMV NZ (Bexsero) in preventing gonococcal infection

To demonstrate efficacy of Bexsero in prevention of urogenital and/or anorectal gonococcal infection. To estimate efficacy of Bexsero in prevention of overall gonococcal infection and by anatomical site (urogenital, anorectal or pharyngeal). To assess safety of Bexsero.