Meningococcal Disease 2022

2022 Annual Report on Meningococcal Disease

In Denmark, invasive meningococcal disease (MD) is clinically notifiable via the clinical notification system (SEI2) of the Danish Health Authority, and monitoring is handled by the Department of Infectious Disease Epidemiology and Prevention (DIDEP) and the Neisseria and Streptococcal Reference Laboratory (NSRL) which receive meningococcal isolates and other biological material from the departments of clinical microbiology. MD covers meningitis, sepsis and culture or DNA detection of meningococci in material from normally sterile locations, e.g. joints. The two monitoring systems continuously supplement each other.

In 2022, the DIDEP received notifications on 16 MD patients. A reminder had to be sent out to ensure notification in three of the cases (19%).

Geography, sex and age

In 2022, the MD incidence was 0.3 per 105 inhabitants, which remains low compared with previous years when the incidence was 0.2 (2021), 0.3 (2020) and 1.0 (2019). The limited number of cases was not clustered in a single Danish area. The incidence in areas where cases were recorded varied from 0.1 to 0.7 cases per 105 inhabitants, see Table 1.


MD occurred in most age groups, see Table 2. The median age was 49 years (range 0-79 years). The highest incidence was recorded in the 1-2-year age group. Please note that the incidence was calculated based on very few cases. The distribution of MD was equal among males and females.



Among the 16 patients, two had meningitis, nine had sepsis and five had both meningitis and sepsis.

A total of ten patients had MD caused by group B (63%), four by group Y (25%) and one by group C (6%). One patient had no information on group (6%).

All patients had become infected in Denmark.

2019 witnessed a considerable increase in group W, which continued into 2020 when 47% of cases were caused by group W. In 2021, one group W case was recorded, whereas no group W cases were registered in 2022.

In 2022, group B dominated, but an increase was also seen in group Y cases. In 2022, group Y was detected only in older adults (age range: 57-79 years).

Since the introduction of restrictions to limit infection with SARS-CoV-2 in March 2020, the number of meningococcal cases has remained lower than was previously the case. This trend continued in 2022.

Laboratory tests

Meningococci were detected by culture in 12 of the 16 cases, and all 12 meningococcal isolates were submitted to the Streptococcal Reference Laboratory. All 12 isolates were fully susceptible to ceftriaxone and ciprofloxacin; 11, to penicillin. The cultures of four cases tested negative to meningococci but were confirmed by nucleic acid amplification technique. For three of these cases, sampling material had been submitted to the Streptococcal Reference Laboratory, enabling grouping by nucleic acid amplification technique.

Underlying diseases and predispositions

Underlying diseases/predispositions and sequelae were established by linking the civil registration numbers (CPR) recorded during the MD monitoring to data from the National Patient Registry.

These conditions were categorised into groups based on diagnosis codes. Infections were included as from one month prior to the current MD case, but no time restrictions were applied for the remaining underlying diseases/predispositions. In eight (50%) of the 16 MD patients registered in 2022, one or more underlying conditions and or predispositions were recorded. Pulmonary disease was the most frequent underlying disease, which was recorded in three patients. The table describing underlying conditions has not been included in this annual report because the number of MD cases with underlying conditions was too low (GDPR). However, the table may be handed out on request, to the extent permitted under current data protection provisions.

Mortality and sequelae

Two patients died due to MD in 2022; a child with unknown serogroup and an adult with group B MD.

Sequelae to MD were recorded in seven patients in 2022. Hearing loss was the most frequently occurring sequelae.

This annual report is also described in EPI-NEWS 45-48/2023.