Invasive meningococcal disease in Germany 2023: Requirement of an adjusted vaccination recommendation?

Introduction

During the COVID-19 pandemic not only a reduction of invasive meningococcal disease (IMD) cases occurred in Germany, but also changes of the affected age-groups and the serogroup distribution. At the end of 2022, the number of IMD started to increase.

Goals

To present laboratory surveillance data of IMD in Germany 2023

Materials and Methods

Data on IMD isolates and clinical samples of suspected IMD cases sent to the National Reference Center for meningococci and Haemophilus influenzae (NRZMHi) were analysed according to antimicrobial susceptibility, age, serogroup and whole genome sequence (WGS).

Results

In 2023, 227 Neisseria meningitidis (Nm) positive samples were submitted to the NRZMHi, of which 193 were viable isolates. Penicillin resistance was detected in 17 (8.8%) isolates of which one harboured a rarely occurring β-lactamase.

The age distribution of the cases was comparable to the pre-pandemic years 2018 and 2019. Most prevalent serogroups were MenB (n=107, 47,1%) and MenY (n=99, 43,6%). MenC (n=7, 3,1%) and MenW (n=10, 4,4%) cases were rare. In comparison to pre-pandemic years, MenY cases increased in the age-groups 15-19 yrs, 20-29 yrs and 80-89 yrs.

WGS data were available for 120 of the 193 meningococcal isolates. cgMLST analysis identified two genetic MenB clusters and ten genetic MenY clusters. The latter belonged to five different sequence type / finetype combinations. The genetic clusters comprised no spatio-temporally related cases.

Summary

The number of IMD cases analysed at the NRZMHi in 2023 was at a level comparable to 2018 and 2019. A major change was the increase of MenY cases from 18.4% in 2019 to 43.6% in 2023. This trend needs to be monitored and considered regarding future vaccination recommendations.