Seroprotection against serogroup C meningococcal disease in adolescents in the United Kingdom: observational studyBMJ 2008; 336 doi: https://doi.org/10.1136/bmj.39563.545255.AE (Published 26 June 2008) Cite this as: BMJ 2008;336:1487
All rapid responses
The article by Snape et al (1) on the persistence of bactericidal antibody titres in adolescents five years after immunisation with one dose of the meningococcal group C glycoconjugate vaccine provides reassuring evidence of continued seroprotection in 84% of the population studied.
However, the authors conclude their study by recommending that a booster dose of MenC vaccine be administered to the cohort of children who will be entering adolescence in the UK in the next five years. They assert that such children, who received primary immunisation in early childhood without the booster dose introduced in 2006, have very low levels of seroprotection and will be susceptible to invasive meningococcal disease and nasopharyngeal carriage of serogroup C meningococcus.
This recommendation is not supported by their study, which did not look for, nor provide, any evidence of increasing nasopharyngeal carriage in preadolescents, and underestimates the protective effect of herd immunity on the cohorts vaccinated in early childhood between 2000 and 2005 who may have lower levels of seroprotection.
Studies of the impact of MenC vaccination have demonstrated a major reduction in the prevalence of nasopharyngeal carriage of serogroup C meningococci after vaccination (2) and a substantial fall in disease incidence in the unvaccinated population indicative of herd immunity (3). The ongoing active post licensure surveillance of meningococcal group C disease in England has not found evidence of reduced effectiveness of the vaccine with time, apart from in infants who are now given a booster dose at one year (4). In 2007/08 (July to June) only 28 laboratory confirmed cases were identified in England and Wales, compared to over 900 cases in the year preceding the introduction of vaccination. Mathematical modelling predicts that high levels of indirect protection against meningococcal group C disease are likely to persist, even if the vaccine only provides 3 years protection against carriage (5). The most recent surveillance data are consistent with model predictions of a continued decline in disease incidence (figure available on request) and suggest that protection against carriage lasts somewhere between 3 and 10 years, with the impact on herd immunity likely to persist for much longer.
Continued post licensure surveillance and ongoing modelling of the impact of herd immunity should be used to inform any future decisions about if, and when, any additional booster doses of MenC vaccine are required.
1. Snape MD, Kelly DF, Lewis S, Banner C, Kibwana L, Moore CE et al. Seroprotection against serogroup C meningococcal disease in adolescents in the UK: observational study BMJ 2008; 336: 1487-1491
2. Maiden MCJ, Ibarez-Pavon AB, Urwin R, Gray SJ, Andrews NJ, Clarke C et al. Impact of meningococcal serogroup C conjugate vaccines on carriage and herd immunity. Journal of Infectious Diseases, 2008: 197: 737 -743
3. Ramsay ME, Andrews NJ, Trotter CL, Kaczmarski EB, and Miller E. Herd immunity from meningococcal serogroup C conjugate vaccination in England: database analysis. BMJ 2003;326:365-366
4. Trotter CL, Andrews NJ, Kaczmarski EB, Miller E and Ramsay ME. Effectiveness of meningococcal serogroup C conjugate vaccine 4 years after introduction. The Lancet, 2004; 364: 365-367
5. Trotter CL, Edmunds WJ, Ramsay ME and Miller E. Modelling future changes to the meningococcal serogroup C conjugate (MCC) vaccine programme in England and Wales. Human Vaccines, 2006: 2: 68-73
Competing interests: None declared
Competing interests: No competing interests