A short review of serogroup C meningococcal conjugate vaccines

From the mid-1980s, a disproportionate increase in serogroup C meningococcal disease associated with a highly virulent strain was observed in a number of countries. As licensed polysaccharide vaccines available at that time could not protect young children and did not provide long-term protection at any age, there was an accelerated development of meningococcal C conjugate (MenC) vaccines. MenC vaccines were introduced into national childhood programmes from late 1999 onwards, usually together with mass catch-up campaigns. MenC vaccine programmes have successfully controlled serogroup C disease in those directly protected through immunisation and, importantly, have also reduced carriage, thereby inducing a herd immunity effect and protecting the wider population. The safety of MenC vaccines was demonstrated in clinical trials and post-licensure evaluation. High levels of effectiveness a year after infant primary immunisation are not sustained, which has led to schedule changes, but protection is better maintained in older age groups and disease control remains good, largely due to the impact on carriage.