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Meningitis and meningococcal epidemiology and sources of surveillance

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Published on: 9th June 2025

  • Surveillance

Epidemiology

Meningococcal disease

The majority of meningococcal infections occur in babies and children aged less than five years of age. There is a smaller, secondary peak in incidence in young adults. 

Most cases of meningococcal disease occur sporadically, with less than 5% of cases occurring in clusters. Outbreaks of meningococcal disease are more common among teenagers and young adults, although still rare. These include outbreaks that have been clustered around schools and universities. Public health interventions may include vaccination (depending on serogroup) and chemoprophylaxis. 

Meningococcal disease shows a seasonal pattern with a peak in winter. In the past 50 years, most meningococcal disease in the UK has been due to group B (MenB) and group C (MenC). The MenC vaccine introduced in 1999 has now successfully reduced cases to just a small number each year. Currently MenB accounts for the vast majority of meningococcal disease.  

Meningococcal disease has a case fatality rate of approximately 5-10%

Meningitis caused by other organisms

The epidemiology of meningitis due to other organisms is more complex to ascertain. Cases of meningitis resulting from infection with measles virus, mumps virus or Haemophililus influeanzae B bacteria have decreased since the introduction of routine childhood vaccination against these diseases. 

After meningococcal disease, invasive infection with the bacterium Streptococcus pneumoniae (also called the pneumococcus) is one of the most frequently reported causes of septicemia (blood poisoning) and meningitis. 

The introduction of vaccination against several pneumococcus serotypes which are particularly associated with causing invasive disease is recommended for those aged over 65, individuals in a high-risk group for infection and for all children (as part of the routine childhood immunisation programme since 2006)

Learn more about meningitis and meningococcal disease

Table of contents:

Sources of surveillance data for Wales

Notification data

It is a statutory requirement in the UK to notify all cases of clinically diagnosed meningitis, whether or not microbiologically confirmed. This statutory requirement for the notification of certain infectious diseases came into being in 1891 and includes all forms of meningitis (whatever the cause). All clinically diagnosed cases of meningococcal septicaemia must also be notified. Notifications in Wales are recorded in the all-Wales case and incident management system, known locally as Tarian. 

Whenever possible, meningitis notifications are sub categorised i.e. meningococcal, pneumococcal, viral, other specified and unspecified. Type of meningitis can often only be determined once confirmed by a laboratory test and may remain unspecified until test results are available. 

One of the main purposes of the notification system is to detect possible outbreaks and epidemics in a timely way. Accuracy of diagnosis is secondary and since 1968 clinical suspicion of a notifiable infection is all that is required. If a diagnosis of meningitis later proves incorrect it should be de-notified, therefore the number reported notifications can change over time.  

Laboratory-confirmed meninogococcal disease

Laboratory-confirmed cases are cases where a sample, usually of blood or spinal fluid, is taken from a patient with symptoms and testing of the sample in a laboratory indicates the presence of meningococcal bacteria, or DNA from those bacteria. Further testing can establish which serogroup of meningococcal bacteria is responsible for disease. 

However, every year there are a number of cases of meningococcal disease which are not confirmed in the laboratory. These are cases where the patient is diagnosed on the basis of symptoms of disease, but there is no confirmation from laboratory tests either because it is not possible to take a sample or treatment (which kills the organism) has started before a sample can be taken. Unconfirmed cases will not be counted in the

Rates of meningitis and meningococcal disease in Wales

Number of notifications of meningococcal septicaemia, total meningitis and specified type of meningitis in Wales: 1999-2024 

Stacked bar chart showing annual notifications of meningitis and septicaemia cases from 2015 to 2025. Categories are meningococcal septicaemia (red), meningococcal meningitis (green), pneumococcal meningitis (purple), viral meningitis (blue), and meningitis other and unspecified (yellow). Total notifications are highest between 2015 and 2019, peaking at around 180 cases in 2017. Notifications decline sharply in 2020 and reach the lowest level, around 50 cases, in 2021. Numbers then increase modestly from 2022 onwards, remaining below pre-2020 levels. Viral meningitis is the largest contributor in most years. Meningococcal septicaemia declines after 2017, while pneumococcal meningitis and other unspecified meningitis remain relatively stable. Total notifications in 2025 are approximately 85 cases.

Source: Public Health Wales Tarian case and incident management system  

Number of notifications of meningococcal septicaemia, total meningitis and specified type of meningitis in Wales: 2015-2025

Year Notifications of meningococcal septicaemia  Total notifications of meningitis  Meningococcal notifications of meningitis  Pneumococcal notifications of meningitis  Viral notifications of meningitis  Unspecified notifications of meningitis 
2015 29 138 23 19 28 39
2016 42 144 9 28 31 34
2017 33 185 23 29 51 49
2018 20 150 19 30 42 39
2019 23 141 13 37 49 19
2020 14 84 9 16 34 11
2021 4 50 5 12 24 5
2022 8 78 9 20 32 9
2023 17 86 13 20 24 12
2024 26 89 20 8 23 12
2025 9 84 15 27 16 17

Source: Public Health Wales Tarian case and incident management system

Number of laboratory reports of Neisseria meningitidis by serogroup in Wales 2010-2025 

Stacked bar chart showing laboratory‑confirmed invasive meningococcal disease cases by year from 2010 to 2025, broken down by serogroup. Most cases are due to MenB across all years. Overall case numbers decline from 2010 to around 2021, with a small increase from 2022 to 2024, followed by a decrease in 2025. Other serogroups (MenC, MenW, MenY and untyped) contribute smaller numbers throughout.

Source: UK Health Security Agency Meningococcal Reference Unit 

Number of laboratory reports of Neisseria meningitidis by serogroup in Wales 2010-2025
Year Group B Group C Group W Group Y Not available Total
2010 74 1 0 3 2 80
2011 61 1 3 6 2 73
2012 67 0 4 2 0 73
2013 50 0 2 1 0 53
2014 35 2 2 7 0 46
2015 24 1 11 4 1 41
2016 33 0 4 6 1 44
2017 16 6 14 7 0 43
2018 17 4 7 0 1 29
2019 17 2 7 4 4 35
2020 14 1 4 1 0 20
2021 2 0 0 0 1 3
2022 11 1 1 0 4 17
2023 23 1 1 1 5 31
2024 42 0 0 1 2 45
2025 21 0 2 0 1 24

Source: UK Health Security Agency Meningococcal Reference Unit, Guidance for the public health management of meningococcal disease

Immunisation

Vaccines are available against certain types of bacterial meningitis and are given as part of the routine childhood and adolescent immunisation programme.  These are meningococci groups B and A, C, W, Y, and pneumococcus and Haemophilus influenzae (HiB), which can also cause meningitis. 

Additionally, vaccination against some other diseases, such as mumps and measles which can cause meningitis, is also part of the childhood immunisation schedule. 

Uptake of routine childhood information is monitored and reported on a quarterly basis through the Wales COVER (Coverage of Vaccinations Evaluated Rapidly) Scheme. Quarterly and Annual reports are available here.

More information on vaccines against meningococcal disease is available below: 


 

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