Epidemiology of Neisseria meningitidis transmission; a case-crossover study

Abstract

Meningococcal disease is a serious public health problem with a case fatality rate of about 10 %. Recent acquisition of the bacteria is generally regarded as an important risk factor for developing the invasive disease. A casecrossover study to examine the effect of transient exposures on the acute outcome, which is the acquisition of Neisseria meningitides, was undertaken.

In the case-crossover design each case serves as its own matched control while case-times are compared to earlier time periods. Data from a longitudinal study was used for a case-crossover analysis. Healthy students aged 14 to 19 were tested for meningococcal carriage and interviewed about potential risk factors. 121 matched pairs of students who were non-carriers in the first survey and became carriers in the second were analysed. Mantel Haenszel Odds Ratios were calculated and a conditional logistic regression analysis was done.