Risk of invasive meningococcal disease in university students in England and optimal strategies for protection using MenACWY vaccine

Abstract

Purpose: In August 2015, in response to increasing group W invasive meningococcal disease (IMD) nationally, a MenACWY vaccine programme was introduced in the UK for 13-18year olds. We reviewed the epidemiology of IMD in young adults and university-associated cases in England during 2014-15 academic year and assessed the potential impact of different immunisation strategies.

Methods: Public Health England national enhanced surveillance data were used to describe the epidemiology of IMD cases in 15-24year olds in England during 2014/15. Relative risks for IMD were calculated overall and by capsular group in students compared with non- student peers for 2014 and 2013 school leavers. Assuming stable future incidence and vaccine efficacy of 90% for five years, we estimated cases averted and numbers needed to vaccinate (NNV) for different MenACWY immunisation programmes: school-based adolescent, GP-based school leaver, and targeting freshers.

Results: Between July 2014 and June 2015, 112 IMD cases were diagnosed in those born between 01/09/1991 and 31/08/2001 (∼15 to 24year-olds). During the 2014/15 academic year (September to June), 49 IMD cases were reported among students attending English universities, including 22 among 2014 school leavers. In this cohort, the relative risk of IMD was higher among students compared to non-students for all capsular groups (RR 11.6; 95% CI 4.7-28.7) and for groups A/C/W/Y (RR 14.8; 95% CI, 4.3-51.5). A school-based programme could potentially have averted 14 cases in 2014/15 and 24 cases over five years with a lower NNV (18,000) than other programmes.

Conclusions: University students, particularly first years entering direct from school, are at higher risk for IMD than non-students. With high vaccine coverage and timely completion, an adolescent school-based MenACWY programme has the greatest potential to prevent cases with the lowest NNV, but population impact through indirect (herd) protection could take longer.

Keywords: Adolescent immunisation programme; Meningococcal W disease; Number needed to vaccinate; Relative risk; Students.