A 3-day workshop, "Vaccine pressure and Neisseria meningitidis", was held in Annecy, France, 9-11 March 2005, to summarize the current state of knowledge regarding N. meningitidis capsule switching and vaccine pressure from capsular polysaccharide-based N. meningitidis vaccines, including conjugates. Main discussion topics were the host-bacteria relationship and N. meningitidis population, worldwide experience of meningococcal vaccination, and using existing experience to shape the future of meningococcal vaccination strategies. The workshop concluded that there is no current evidence to suggest that serogroup C conjugate vaccine pressure has resulted in meningococcal serogroup switching or replacement.