Changes in the Population Structure of Invasive Neisseria meningitidis in the United States After Quadrivalent Meningococcal Conjugate Vaccine Licensure

J Infect Dis. 2015 Jun 15;211(12):1887-94. doi: 10.1093/infdis/jiu842. Epub 2015 Jan 2.


Background: Meningococcal conjugate vaccines against serogroups A, C, W, and Y (MenACWY) are recommended for routine use in adolescents aged 11-18 years. The impact of these vaccines on the meningococcal population structure in the United States have yet to be evaluated.

Methods: Meningococcal isolates recovered during 2006-2010 (ie, after introduction of MenACWY) collected through Active Bacterial Core surveillance (ABCs) were characterized; serogroup distribution and molecular features of these isolates were compared to previously published data on ABCs isolates recovered from 2000 to 2005 (ie, before introduction of MenACWY). P values were generated using χ(2) statistics and exact methods.

Results: There was a significant change (P < .05) in serogroup distribution among all age groups between the 2 periods. A small proportion of isolates showed evidence of capsular switching in both periods. Between the 2 periods, significant changes were observed in the distribution of porin A, ferric enterobactin transport, and strain genotypes among vaccine and nonvaccine serogroups.

Conclusions: The population structure of US meningococcal isolates is dynamic; some changes occurred over time, but the basic structure remained. Vaccine-induced serogroup replacement was not observed, although a small proportion of isolates had undergone capsule switching, possibly driven by non-vaccine-mediated selection. Changes in the distribution of molecular features are likely due to horizontal gene transfer and changes in serogroup distribution.

Keywords: meningococcal disease; molecular epidemiology; vaccine impact.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Female
  • Genotype
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Meningococcal Infections / epidemiology*
  • Meningococcal Infections / microbiology*
  • Meningococcal Infections / prevention & control
  • Meningococcal Vaccines / administration & dosage*
  • Middle Aged
  • Neisseria meningitidis / classification*
  • Neisseria meningitidis / genetics
  • Neisseria meningitidis / immunology
  • Neisseria meningitidis / isolation & purification*
  • Serogroup
  • United States
  • Vaccines, Conjugate / administration & dosage
  • Young Adult


  • MenACWY
  • Meningococcal Vaccines
  • Vaccines, Conjugate