Meningococcal carriage in Norwegian teenagers: strain characterisation and assessment of risk factors

Epidemiol Infect. 2020 Mar 31:148:e80. doi: 10.1017/S0950268820000734.

Abstract

Teenagers have a higher risk of invasive meningococcal disease (IMD) than the general population. This cross-sectional study aimed to characterise strains of Neisseria meningitidis circulating among Norwegian teenagers and to assess risk factors for meningococcal carriage. Oropharyngeal swabs were collected from secondary-school students in southeastern Norway in 2018-2019. Meningococcal isolates were characterised using whole genome sequencing. Risk factors for meningococcal carriage were assessed from questionnaire data. Samples were obtained from 2296 12-24-year-olds (majority 13-19-year-olds). N. meningitidis was identified in 167 (7.3%) individuals. The highest carriage rate was found among 18-year-olds (16.4%). Most carriage isolates were capsule null (40.1%) or genogroup Y (33.5%). Clonal complexes cc23 (35.9%) and cc198 (32.3%) dominated and 38.9% of carriage strains were similar to invasive strains currently causing IMD in Norway. Use of Swedish snus (smokeless tobacco) (OR 1.56, 95% CI 1.07-2.27), kissing >two persons/month (OR 2.76, 95% CI 1.49-5.10) and partying >10 times/3months (OR 3.50, 95% CI 1.45-8.48) were associated with carriage, while age, cigarette smoking, sharing of drinking bottles and meningococcal vaccination were not. The high meningococcal carriage rate among 18-year-olds is probably due to risk-related behaviour. Use of Swedish snus is possibly a new risk factor for meningococcal carriage. Almost 40% of circulating carriage strains have invasive potential.

Keywords: Carriage; Neisseria meningitidis; Swedish snus; meningococcal vaccines; smokeless tobacco; teenager; whole genome sequencing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Child
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Meningococcal Infections / epidemiology*
  • Meningococcal Infections / microbiology
  • Neisseria meningitidis / genetics
  • Neisseria meningitidis / isolation & purification*
  • Norway / epidemiology
  • Phylogeny
  • Risk Factors
  • Young Adult