Failure of meningococcal vaccination to stop the transmission of meningococci in Nigerian schoolboys

Abstract
A combined group A and group C meningococcal polysaccharide vaccine was given to 438 Nigerian schoolboys shortly before an outbreak of group A meningococcal disease occurred in their school. Four months after vaccination the carriage rate of group A meningococci among vaccinated subjects (11%) was no different from that found among the controls (12%), although a good antibody response to both components of the vaccine was observed. One case of group A meningococcal disease was recorded amongst 438 vaccinated subjects while 5 cases occurred among 874 controls.