Meningococcal disease

Background

Meningococcal disease is an invasive infection of Neisseria meningitidis (N. meningitidis) in:

  • blood
  • cerebrospinal fluid (CSF)
  • other normally sterile site

Meningococcal disease cases overwhelmingly show symptoms of meningitis (inflammation of the meninges) or septicaemia (blood poisoning). It can also present as a combination of both or as a rarer clinical presentation, such as joint infection. Meningitis can be caused by a variety of viruses or bacteria, of which N. meningitidis is one. Meningococcal disease is a significant cause of morbidity and mortality in children and young adults.

Although approximately 10% of the population are estimated to carry N. meningitidis in the nasopharynx, the vast majority do not have symptoms or develop invasive disease. Invasive cases acquire infection through inhalation of or direct contact with respiratory droplets, from either an infected person or asymptomatic carrier.

N. meningitidis is classified according to its outer membrane characteristics via a process known as serogrouping. There are a number of different serogroups, the most common of which in the UK is B followed by W. Cases of serogroup Y, Z and C disease have also been also reported.

Guidance

Data and analysis of meningococcal disease is also available on the Public Health England website.

For more information on meningococcal immunisation, including updates, please refer to the PHE Green Book, Chapter 22.

The National Education for Scotland (NES) website provides healthcare professionals with training and educational materials for:

Public information can be found by visiting the NHS inform website.

For all infection prevention and control guidance visit the A-Z ​pathogens section of the National Infection and Prevention Control Manual.

Data and surveillance

In 1999 the Meningococcal Invasive Disease Augmented Surveillance (MIDAS) system was introduced. The surveillance scheme is managed jointly by ourselves and the Scottish Haemophilus Legionella Meningococcus and Pneumococcus Reference Laboratory (SHLMPRL). Surveillance data is from MIDAS informs the epidemiology of meningococcal disease in Scotland, as analyses can be conducted according to:

  • age
  • serogroup
  • molecular typing
  • clinical presentation
  • outcome

Surveillance update for 2018

Between October and December 2018 (weeks 40 to 52), 16 cases of meningococcal disease were reported, bringing the total number of cases reported for the year to 74. Figure 1 shows that total case numbers for 2017 and 2018 are at their lowest since 2008.

Figure 1 is a line graph showing the cumulative number of meningococcal cases reported to MIDAS per week, by year. Each line represents a different year from 2008 to the fourth quarter of 2018. Total number of cases for 2018 were similar to those observed in 2017 and are low in comparison to previous years (with the exception of 2014).

Figure 2 shows number of meningococcal disease cases for 2018, according to age group and by quarter:

  • 11 cases, which is 14.9%, were aged under one year
  • six cases, which is 8.1%, were aged one to four years
  • 19 cases, which is 25.7%, were aged five to 24 years
  • 38 cases, which is 51.4%, were aged 25 years and over

Figure 2 is a line graph showing the number of meningococcal cases reported to MIDAS per quarter, by year. The data ranges from 2001 to the fourth quarter of 2018 and each line on the graph represents number of cases for each age group (and total number of cases). Historically, cases have been more frequent in the under five age group. However, since 2016 those aged above 25 years have overtaken the under fives as the group with highest number of cases. Quarter one of 2018, saw a peak in reports of meningococcal disease, for those aged between five and 24 years old with a corresponding reduction in reports for those under the age of five (which subsequently peaked during Quarter two).

Serogroup was identified for 59 (79.7%) of the 74 cases reported in 2018, as demonstrated in Figure 3:

  • 37, which is 50%, were serogroup B
  • 11, which is 14.9%, were serogroup W
  • five, which is 6.8%, were serogroup C
  • two, which is 2.7%, were serotype Y
  • one, which is 1.4%, were serotype Z

Of the remaining 18 notifications:

  • 15, or 20.3%, were based on clinical diagnoses and no serogroup is likely to become available
  • three, or 4.1%, were microbiologically confirmed but no serogroup could be detected

Figure 3 is a stacked bar chart showing the number of meningococcal cases reported to MIDAS per year, from 1999 to the fourth quarter of 2018. The bars are subdivided by meningococcal serogroup and until 2001, predominant serogroups were B and C (in addition to clinically diagnosed infections). However the number of group C infections decreased rapidly after 2001 and since 2012, serogroup B infections comprise the majority of laboratory confirmed cases. In 2016, laboratory reports of serogroup C infection increased, alongside serogroup W infections.

There were 37 cases of serogroup B reported in 2018, which is within the annual range of 33 to 48 total cases reported from 2012 to 2017. Of the 37 serogroup B cases, eight (21.6%) were under five years of age as compared to 51.5% of cases in 2017.

Six of the serogroup B cases reported in 2018 were born on or after 1 July 2015 making them eligible for routine immunisation with Men B vaccine at the age of two months. Of these:

  • none had been fully vaccinated according to the recommended routine schedule of three doses
  • one case had received one dose of Men B vaccine according to the childhood vaccination schedule
  • four cases had received two doses of Men B vaccine according to the childhood vaccination schedule
  • one case was eligible for vaccination but had not received it

The Men B vaccine is not expected to protect against all serogroup B strains and further detailed microbiological testing is required in order to evaluate the full impact of the vaccine.

Serogroup W cases continue to be reported separately following introduction of the Men ACWY immunisation programme in summer 2015 (Figure 4). During 2018, 11 (14.9%) serogroup W cases were reported which is a decrease in comparison to 18 (25%) during 2017 and 25 (23.1%) in 2016.

Figure 4 demonstrates a positive impact of the MenACWY vaccine for the eligible population. In 2018, seven (63.6%) of the 11 serogroup W cases were in adults aged 25 years and older (none of whom were vaccinated for Men ACWY), three (27.3%) in children under five years and one case (9%) from the five to 14 years age group. There were no serogroup W cases recorded for the age group eligible for Men ACWY vaccination (18-24 years), as compared to five in 2017 (four of whom were unvaccinated and one vaccination status unknown).  

Following introduction of the Men C vaccine, serogroup C cases declined and were rarely reported in Scotland until 2016, when there was an increase. During 2018, five cases of serogroup C were reported, in comparison to eight cases in 2017 and 13 in 2016. Four of the 2018 serogroup C cases had not been immunised with Men C vaccine as their age deemed them ineligible for vaccination. The remaining case had been fully immunised, with the last dose more than 10 years prior to infection.

Figure 4 is a line graph showing the number of serogroup W cases reported from 2009 to the fourth quarter of 2018, by age group. From 2014 to 2016 there was an increase in serogroup W amongst all age groups with exception of those aged 5-14 years. Since 2017, serogroup W decreased for those aged 15 years and above, remained stable in the 5-14 age group and increased slightly for the  under 5 age group.

 

Information on clinical presentation was available for 73 (98.6%) cases reported in 2018, of which:

  • 22, which is 30.1% were recorded as presenting with meningitis
  • 24, which is 32.9%, with septicaemia
  • 20, which is 27.4%, with meningitis and septicaemia
  • One, which is 1.4%, with peri-orbital cellulitis

The remaining six were recorded as ‘other’ presentations and included:

  • gastro-intestinal symptoms
  • respiratory symptoms
  • fever
  • confusion
  • headache
  • lethargy

Number of deaths between 2002 and 2018, reported by serogroup and with case fatality ratio is shown in Figure 5. Five deaths from meningococcal disease have been reported to MIDAS during 2018 with a 6.8% case fatality ratio. Four deaths occurred for serogroup B cases and for one death serogroup was not determined. All were in unvaccinated adults aged 20 years or older, which is similar to that reported over the previous three years.

Figure 5 is a stacked bar chart showing the number of deaths from meningococcal cases reported to MIDAS per year. The bars are subdivided by meningococcal serogroup and there is a line showing the case fatality rate (CFR) each year. The overall trend is varied, with the highest number of deaths in 2004 (15 deaths, 10% CFR) and the lowest in 2012 (2 deaths, 2% CFR). Serogroup B and clinically diagnosed cases make up the majority of deaths per year and account for all deaths in 2018. During the three quarters of 2018, there were four deaths reported with a CFR of 6.8%. Four were serogroup B infections and one based on clinical diagnosis.

Vaccination

The MenB vaccine was introduced into the routine childhood vaccination programme on 1 September 2015. All children born from 1 July 2015 were offered the Men B vaccine at two, four and 12 months of age, alongside other routine childhood vaccinations. A catch-up programme was rolled out for children born after 1 May 2015. Children born before 1 May 2015 are not eligible to receive the MenB vaccine.

The combined Hib and MenC vaccine given in the UK is called Menitorix® and it's included in the UK childhood immunisation schedule, with routine vaccination recommended between 12 and 13 months of age. Further information about MenC vaccination is available from the NHS inform website.

MenACWY vaccine was recommended by the Joint Committee on Vaccination and Immunisation (JCVI) and offered to 14 to 18 year olds as a measure to address an increasing number of meningococcal serogroup W cases in this age group. A phased catch-up programme also ran in Scotland between August 2015 and March 2016. The vaccine was also offered to students under the age of 25 attending university for the first time from Autumn 2015. MenACWY vaccine continues to be offered routinely to those in secondary school year 3 (S3).

Read more about the introduction of the meningitis B vaccine to students under the age of 25 on the Scottish Government website.


Vaccine information


Vaccine uptake statistics

Vaccine uptake statistics can be found on the Information Services Division website.