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 HPS and the Scottish Haemophilus Legionella Meningococcus and Pneumococcus Reference Laboratory (SHLMPRL). Surveillance data is from MIDAS informs the epidemiology of meningococcal disease in Scotland.

Surveillance update for April to June 2020

Three cases of meningococcal disease were reported between April and June 2020 (weeks 14 to 26), bringing the total for the first two quarters of the year to 24. This is lower than the number of cases for the corresponding period in the previous four years (range 32 to 59), as shown in Figure 1.

Figure 1: Cumulative number of meningococcal disease cases reported to MIDAS, 2016 to 2020 (to week 26)

Figure 1 is a series of line graphs showing the cumulative number of meningococcal cases reported to MIDAS per week, by year. Each line represents a different year from 2016 to the end of the second quarter of 2020. The number of cases in 2020 is lower than for the corresponding period in 2019.

Figure 2 shows the number of meningococcal disease cases, according to age group and by quarter from 2001. Of the 24 cases reported in the first and second quarter of 2020: 

  • two (8.3%) were aged under one year
  • one (4.2%) was aged one to four years
  • nine (37.5%) were aged five to 24 years
  • twelve (50.0%) were aged 25 years and over

Figure 2: Meningococcal disease cases reported to MIDAS by age group and quarter, 2001 to 2020 (to week 26)

Figure 2 is a series of line graphs showing the number of meningococcal cases reported to MIDAS per quarter, by year. The data ranges from 2001 to the end of the second quarter of 2020 and each line on the graph represents number of cases for a specific age group, and there is a line for the 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 overall.

Serogroup was identified for 17 (70.8%) of the 24 cases reported in the first and second quarter of 2020, as shown in Figure 3:

  • 11 (45.8%) were serogroup B
  • four (16.7%) were serogroup W
  • one (4.2%) was serogroup Y
  • one (4.2%) was serogroup C

Of the remaining seven (29.2%) notifications, six were based on clinical diagnosis, with no serogroup likely to become available, while the other was caused by a non-groupable Neisseria meningitidis strain.  

Figure 3: Meningococcal disease cases reported to MIDAS by serogroup, 1999 to 2020 (to week 26)

Figure 3 is a bar chart showing the number of meningococcal cases reported to MIDAS by serogroup, from 1999 to the end of the second quarter of 2020. 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.

Of the 11 serogroup B cases reported to the end of the second quarter of 2020, two (18.2%) were under five years of age. Both cases under five years of age were born on or after 1 July 2015, making them eligible for routine immunisation with Men B vaccine at the age of eight weeks. One case had received three doses of Men B vaccine according to the childhood vaccination schedule, and the other had received one dose of Men B vaccine.

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 MenACWY immunisation programme in summer 2015. Figure 4 demonstrates a positive impact of the MenACWY vaccine for the eligible population. Four serogroup W cases were reported to the end of the second quarter of 2020, which is lower than the nine cases reported for the same period in 2019. All four serogroup W cases were in adults aged 25 years and older. There were no serogroup W cases recorded in the 18-24 year age group, who would have been eligible for MenACWY vaccination. 

Following introduction of the Men C vaccine, serogroup C cases declined and were rarely reported in Scotland until 2016, when there was an increase. One serogroup C case was reported in the first two quarters of 2020, which is the same as for the corresponding period in 2019. This case was unvaccinated with Men C vaccine.

Figure 4: Meningococcal serogroup W cases by age group reported to MIDAS, 2009 to 2020 (to week 26)

Figure 4 is a series of line graphs showing the number of serogroup W cases reported from 2009 to the end of the second quarter of 2020, by age group. From 2014 to 2016 there was an increase in serogroup W amongst all age groups with exception of those aged 5 to 14 years. Since 2017, serogroup W case numbers have decreased in those aged under 25 years.

Information on clinical presentation was available for 23 of the 24 cases:

  • nine (39.1%) were recorded as presenting with meningitis
  • nine (39.1%) with septicaemia
  • two (8.7%) with meningitis and septicaemia
  • one (4.3%) with peri-orbital cellulitis
  • one (4.3%) with chest infection
  • one (4.3%) with pyrexia, confusion and dyspnea

Number of deaths from between 2002 and the end of the second quarter of 2020, reported by serogroup is shown in figure 5, and case fatality ratio is shown in Figure 6. Two deaths from meningococcal disease were reported to MIDAS to the end of the second quarter of 2020, with a case fatality ratio of 8.3%. Both deaths occurred in clinically diagnosed cases for whom serogroup was not available. 

Figure 5: Meningococcal deaths by serotype reported to MIDAS, 2002 to 2020 (to week 26)

Figure 5 is a bar chart showing the number of deaths from meningococcal cases reported to MIDAS by serogroup, from 2002 to the end of the second quarter of 2020. The overall trend is varied, with the highest number of deaths in 2004 (15 deaths) and the lowest in 2012 (two deaths). There were two deaths in the first quarter of 2020, both of which were clinically diagnosed cases.

Figure 6: Meningococcal disease case fatality ratio, 2002 to 2020 (to week 26)

Figure 6 is a line graph showing meningococcal disease case fatality ratio from 2002 to the end of the second quarter of 2020. The case fatality ratio for the first and second quarters of 2020 is 8.3%.

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 eight weeks, 16 weeks 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).


Vaccine information


Vaccine uptake statistics

Vaccine uptake statistics are published by Public Health Scotland Data and Intelligence.