UKMenCar4: A cross-sectional survey of asymptomatic meningococcal carriage amongst UK adolescents at a period of low invasive meningococcal disease incidence.
Bratcher HB., Rodrigues CMC., Finn A., Wootton M., Cameron JC., Smith A., Heath P., Ladhani S., Snape MD., Pollard AJ., Cunningham R., Borrow R., Trotter C., Gray SJ., Maiden MCJ., MacLennan JM.
Carriage of Neisseria meningitidis, the meningococcus, is a prerequisite for invasive meningococcal disease (IMD), a potentially devastating infection that disproportionately afflicts infants and children. Humans are the sole known reservoir for the meningococcus, and it is carried asymptomatically in the nasopharynx of ~10% of the population. Rates of carriage are dependent on age of the host and social and behavioural factors. In the UK, meningococcal carriage has been studied through large, multi-centre carriage surveys of adolescents in 1999, 2000, and 2001, demonstrating carriage can be affected by immunisation with the capsular group C meningococcal conjugate vaccine, inducing population immunity against carriage. Fifteen years after these surveys were carried out, invasive meningococcal disease incidence had declined from a peak in 1999. The UKMenCar4 study was conducted in 2014/15 to investigate rates of carriage amongst the adolescent population during a period of low disease incidence. The protocols and methodology used to perform UKMenCar4, a large carriage survey, are described here.