a1 PHLS Communicable Disease Surveillance Centre, Abton House, Wedal Road, Roath, Cardiff CF4 3QX
a2 Department of Public Health Medicine, Powys Health, Mansion House, Bronllys Hospital, Bronllys, Powys LD3 OLU
a3 3Public Health Laboratory, County Hospital, Hereford HR1 2ER
As part of the management of an outbreak of meningococcal infection, 119 school contacts of an index case were swabbed for nasopharyngeal carriage. In a cohort study, risk factors for Neisseria meningitidis carriage were ascertained by means of a questionnaire, completed by 114 (96%) of those swabbed.
Twenty five (21%) cultures were identified as ‘neisseria positive’; of which there were 18 (15%) Neisseria meningitidis isolates, 2 (2%) Neisseria lactamica isolates and 5 (4%) showed contaminants only. Two (2%) carriers were identified as harbouring the implicated outbreak strain. Single variable analysis identified six statistically significant risk factors for meningococcal carriage; increasing age, female sex, manual social class, personal smoking, regular attendance at a discotheque and rhinorrhoea. Multivariate analysis, using logistic regression modelling, found that of these six variables only age, sex and social class remained statistically significant when the other factors were controlled for. Nevertheless the role of smoking, social events and respiratory/viral infections in nasopharyngeal carriage, and other plausible mechanisms whereby age, sex and social class might exert their effect, could usefully be investigated further.
(Accepted April 21 1996)
c1 Dr A. L. Davies, Department of Public Health Medicine, Shropshire Health, William Farr House, Royal Shrewsbury Hospital, Shrewsbury, Shropshire SY3 8XL.