Herd immunity from meningococcal serogroup C conjugate vaccination in England: database analysis
BMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7385.365 (Published 15 February 2003) Cite this as: BMJ 2003;326:365
- Mary E Ramsay, consultant epidemiologist (mramsay@phls.org.uk)a,
- Nick J Andrews, statisticiana,
- Caroline L Trotter, research scientista,
- Edward B Kaczmarski, consultant microbiologistb,
- Elizabeth Miller, head of immunisation divisiona
- aPublic Health Laboratory Service Communicable Disease Surveillance Centre, London, NW9 5EQ,
- b Public Health Laboratory Service Meningococcal Reference Unit, Manchester Public Health Laboratory, Manchester M20 2LR
- Correspondence to: M E Ramsay
- Accepted 7 November 2002
In November 1999, the United Kingdom introduced routine meningococcal serogroup C conjugate vaccination for infants. The vaccine was also offered to everyone aged under 18 years in a phased catch-up programme.1 The first to be vaccinated were adolescents, and the entire programme was completed by the end of 2000. On the basis of direct protection provided by the vaccine, 1 2 this catch-up programme was likely to be cost effective.3
Maiden et al described a 67% reduction (from 0.45% to 0.15%) in the prevalence of nasopharyngeal carriage of serogroup C meningococci in adolescents before and after the vaccination programme.4 A fall in meningococcal carriage would be expected to reduce exposure among unvaccinated children and therefore to enhance the effectiveness of meningococcal conjugate vaccine. We present rates of disease in vaccinated and unvaccinated children to provide the first evidence of an indirect effect from meningococcal conjugate vaccine.
Methods and results
Since December 1999 we have investigated the vaccination history of all cases of …