Impact of meningococcal C conjugate vaccine in the UK.

This review details the impact of the introduction of meningococcal serogroup C conjugate (MCC) vaccines in the UK. An overall reduction of 86.7% in the incidence of serogroup C infection in the targeted age groups has been observed from 1999 to 2001, with a concomitant decrease in deaths, from 67 in 1999 to 5 in 2001. The enhanced surveillance programme initiated to complement the introduction of MCC vaccines has been essential in generating data relating to vaccine coverage, vaccine failures and efficacy estimates. Vaccine coverage has exceeded 80% in all age groups targeted and up to the end of 2001, 25 confirmed and 1 probable vaccine failure have been observed in England and Wales. Efficacy estimates for England up to September 2001 were 91.5% in infants receiving three doses of MCC vaccine and 89.3% in toddlers receiving one dose of MCC vaccine (England). There is some evidence of herd immunity in unvaccinated cohorts of the target age groups, ranging from a reduction in disease incidence of 34% in 9-14 year olds to 61% in 15-17 year olds. Surveillance of the genotypic and phenotypic characteristics of invasive and carriage isolates has shown no evidence to date of capsular switching from serogroup C to serogroup B.