Recent increased incidence of invasive serogroup W meningococcal disease: A retrospective observational study

Nichlas Hovmand,Lene Fogt Lundbo,Gitte Kronborg,Sidsel Skou Voss,Håkon Sandholdt,Steen Hoffmann,Palle Valentiner-Branth,Thomas Benfield

doi:10.1016/j.ijid.2021.05.086

Abstract

ObjectivesNeisseria meningitidis serogroup W incidence has increased. Mortality associated with serogroup W has been higher than for other serogroups. Here we report epidemiological characteristics and risks of poor outcomes associated with invasive meningococcal disease in Denmark since 1980. MethodsAll cases of invasive meningococcal disease reported from 1980–2018 were analyzed. Incidence rates by age, sex, manifestation, and serogroup were calculated. Poisson regression was used to analyze the rise in serogroup W, and multivariate logistic analysis was used to analyze risk factors for mortality. ResultsA total of 5825 cases were analyzed. Risk of serogroup W infection increased after 2015 compared with all previous periods. Younger (<20 years) and older age (≥60 years) was associated with an increased risk of serogroup W infection compared with being aged 20–39. Crude case fatality was 12.0%, 11.9%, 9.2%, and 7.9% for serogroups W, Y, C, and B, respectively. After adjustment for age, sex, and manifestation, 30-day mortality was comparable for serogroups. Older age and manifestation with sepsis independently predicted risk of death. ConclusionsInvasive meningococcal disease caused by serogroup W has increased, but serogroup per se was not associated with an increased risk of 30-day mortality.

Highlights

Invasive meningococcal disease (IMD) remains a significant global burden of disease, but the relative contribution of serogroups A, B, C, W, X, and Y have varied over time (Domingo et al, 2019; Hart and Thomson, 2006; Okike et al, 2014; Oordt-Speets et al, 2018)
We report an overall decline in IMD cases in Denmark since the mid-1980s but a significant increase in IMD-W in recent years, which is in line with reports from most countries, demonstrating the unpredictable nature of meningococcal disease epidemiology
There was a tendency to an increased case fatality rate (CFR) for IMD-W in the unadjusted analysis that disappeared in the adjusted analysis, where old age and manifestation with sepsis were independent risk factors for death

Summary

Introduction

Invasive meningococcal disease (IMD) remains a significant global burden of disease, but the relative contribution of serogroups (sg) A, B, C, W, X, and Y have varied over time (Domingo et al, 2019; Hart and Thomson, 2006; Okike et al, 2014; Oordt-Speets et al, 2018). Several reports have shown increases of sg-W in carriers of Neisseria meningitidis and Abbreviations: CFR, case fatality rate; Cc11, clonal complex 11; IMD, invasive meningococcal disease; IQR, interquartile range; OR, Odds ratio; Sg, serogroup; SSI, Statens Serum Institut. Cases of IMD (Loenenbach et al, 2020; Booy et al, 2019; von Gottberg et al, 2008; Eriksson et al, 2018; Korzeniewski and Konior, 2018; Lucidarme et al, 2015; Carville et al, 2016; Neal et al, 2000; Ladhani et al, 2015; Meiring et al, 2019; Sáfadi et al, 2013; Abad et al, 2014; Constenla et al, 2015). The associated increased risk of death by W has been suggested to be caused by sg-W’s predilection to cause sepsis and, in some reports, to infect older individuals (Loenenbach et al, 2020; von Gottberg et al, 2008; Ladhani et al, 2015; Howitz et al, 2009)

Objectives

Methods

Results

Conclusion