Neisseria meningitidis carriage and risk factors among teenagers in Suizhou city in China

Abstract

Teenagers are important carriers of Neisseria meningitidis, which is a leading cause of invasive meningococcal disease. In China, the carriage rate and risk factors among teenagers are unclear. The present study presents a retrospective analysis of epidemiological data for N. meningitidis carriage from 2013 to 2017 in Suizhou city, China. The carriage rates were 3.26%, 2.22%, 3.33%, 3.53% and 9.88% for 2013, 2014, 2015, 2016 and 2017, respectively. From 2014 to 2017, the carriage rate in the 15- to 19-year-old age group (teenagers) was the highest and significantly higher than that in remain age groups. Subsequently, a larger scale survey (December 2017) for carriage rate and relative risk factors (population density, time spent in the classroom, gender and antibiotics use) were investigated on the teenagers (15- to 19-year-old age) at the same school. The carriage rate was still high at 33.48% (223/663) and varied greatly from 6.56% to 52.94% in a different class. Population density of the classroom was found to be a significant risk factor for carriage, and 1.4 persons/m2 is recommended as the maximum classroom density. Further, higher male gender ratio and more time spent in the classroom were also significantly associated with higher carriage. Finally, antibiotic use was associated with a significantly lower carriage rate. All the results imply that attention should be paid to the teenagers and various measures can be taken to reduce the N. meningitidis carriage, to prevent and control the outbreak of IMD.

Keywords: Carriage; Neisseria meningitidis; risk factors; teenagers.

Fig. 1.

Carriage rates for different classes according to location. The carriage rates (data in every classroom) varied greatly in different classes. In the two classes recruited both in November 2017 and December 2017, there was no significant difference in carriage rate between the two surveys.

Fig. 2.

Association between population density and carriage rate. The carriage rate and the population density for all the recruited class are shown in the figure. A density of 1.4 persons/m² might be a critical point beyond which the carriage rates increase to above 40%. The carriage rate for classes with a population density of over 1.4 persons/m² is significantly higher than that for classes with a density below 1.4 persons/m².