Limited Impact of Adolescent Meningococcal ACWY Vaccination on Neisseria meningitidis Serogroup W Carriage in University Students

J Infect Dis. 2018 Jan 30;217(4):608-616. doi: 10.1093/infdis/jix596.


Background: In the United Kingdom, rising levels of disease due to Neisseria meningitidis serogroup W clonal complex (cc) sequence type (ST) 11 (MenW:cc11) strains led to introduction of meningococcal conjugate vaccine (MenACWY) for teenagers. We investigated the impact of immunization on carriage of meningococci targeted by the vaccine, using whole-genome sequencing of isolates recovered from a cohort of vaccinated university students.

Methods: Strain designation data were extracted from whole-genome sequencing data. Genomes from carried and invasive MenW:cc11 strains were compared using a gene-by-gene approach. Serogrouping identified isolates expressing capsule antigens targeted by the vaccine.

Results: Isolates with a W: P1.5,2: F1-1: ST-11 (cc11) designation and belonging to the emerging 2013-strain of the South American-United Kingdom MenW:cc11 sublineage were responsible for an increase in carried group W strains. A multifocal expansion was evident, with close transmission networks extending beyond individual dormitories. Carried group Y isolates were predominantly from cc23 but showed significant heterogeneity, and individual strain designations were only sporadically recovered. No shifts toward acapsulate phenotypes were detected in targeted meningococcal populations.

Conclusions: In a setting with high levels of MenACWY use, expansion of capsule-expressing isolates from the 2013-strain of MenW:cc11 but not MenY:cc23 isolates is indicative of differential susceptibilities to vaccine-induced immunity.

Keywords: Neisseria; carriage; epidemiology; genome sequencing; meningitidis; serogroup W; serogroup Y; vaccine; whole.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Cross-Sectional Studies
  • Disease Transmission, Infectious / prevention & control*
  • Female
  • Genotype
  • Humans
  • Male
  • Meningococcal Infections / epidemiology*
  • Meningococcal Infections / microbiology
  • Meningococcal Infections / prevention & control*
  • Meningococcal Vaccines / administration & dosage*
  • Meningococcal Vaccines / immunology
  • Neisseria meningitidis / classification
  • Neisseria meningitidis / genetics
  • Neisseria meningitidis / immunology
  • Neisseria meningitidis / isolation & purification*
  • Serogroup*
  • Students
  • Treatment Outcome
  • United Kingdom / epidemiology
  • Universities
  • Vaccines, Conjugate / administration & dosage
  • Vaccines, Conjugate / immunology
  • Whole Genome Sequencing
  • Young Adult


  • MenACWY
  • Meningococcal Vaccines
  • Vaccines, Conjugate