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 April to June 2019

Between April and June 2019 (weeks 14 to 26), 11 cases of meningococcal disease were reported, bringing the total number of cases in the first to quarters of 2019 to 32. This is lower than the number of cases for the same period in the previous four years (range 37 to 59), as shown in figure 1.

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 2015 to the second quarter of 2019. The number of cases for the first quarter of 2019 is lower than that for the same period of the previous four years.

Figure 2 shows number of meningococcal disease cases, according to age group and by quarter from 2001. Of the 32 cases reported in the first two quarters of 2019: 

  • five (15.6%) were aged under one year
  • two (6.3%) were aged one to four years
  • 10 (31.3%) were aged five to 24 years
  • 15 (46.9%) 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 second quarter of 2019 and each line on the graph represents number of cases for each age group, as well as 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 26 (81.3%) of the 32 cases reported in the first two quarters of 2019, as shown in Figure 3:

  • 14 (43.8%) were serogroup B
  • nine (28.1%) were serogroup W
  • two (6.3%) were serogroup Y
  • one (3.1%) was serogroup C

The remaining six (18.9%) notifications were based on clinical diagnosis, and no serogroup is likely to become available.

Figure 3 is a stacked bar chart showing the number of meningococcal cases reported to MIDAS per year, from 1999 to the second quarter of 2019. 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 14 cases of serogroup B reported to the second quarter of 2019.Of the 14 serogroup B cases, five (35.7%) were under five years of age. All five 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 two months. Of these:

  • one case had received three doses of Men B vaccine according to the childhood vaccination schedule
  • one case had received two doses of Men B vaccine according to the childhood vaccination schedule
  • two cases had received one dose of Men B vaccine according to the childhood vaccination schedule
  • one case was unvaccinated against Men B

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. Nine serogroup W cases were reported to the second quarter of 2019, which compares to ten cases for the same period in 2018. Of the nine serogroup W cases, one (11.1%) was in a child aged under five years old, and eight (88.9%) were in adults aged 25 years and older. There were no serogroup W cases recorded for the group eligible for MenACWY vaccination (18 to 24 years). 

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 2019. This compares to three serogroup C cases for the same period in 2018. The serogroup C case was fully immunised with Men C vaccine.

Figure 4 is a line graph showing the number of serogroup W cases reported from 2009 to the second quarter of 2019, 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 decreased for those aged 15 years and above, remained stable in the 5 to 14 age group and increased slightly for the under 5 age group.

Information on clinical presentation was available for all 32 cases:

  • 14 (43.8%) were recorded as presenting with septicaemia
  • ten (31.3%) with meningitis
  • five (15.6%) with meningitis and septicaemia
  • one (3.1%) with joint infection
  • one (3.1%) with septicaemia and joint infection
  • one (3.1%) with chest infection

Number of deaths between 2002 and March 2019, reported by serogroup and with case fatality ratio is shown in Figure 5. Four deaths from meningococcal disease were reported to MIDAS between January and June 2019, with a 12.5% case fatality ratio. Two deaths occurred in serogroup W cases. Both were in adults aged over 25 years, one of whom was unvaccinated. Vaccination status was unknown for the other.  One death occurred in a serogroup B case who was partially vaccinated. One death occurred in a clinically diagnosed case for whom serogroup was not available. 

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 each year. The overall trend is varied, with the highest number of deaths in 2004, with 15 deaths or 10% case fatality rate, and the lowest in 2012, with two deaths or 2% case fatality rate. Serogroup B and clinically diagnosed cases make up the majority of deaths each year. There were four deaths in the first two quarters of 2019, two of which were serogroup W cases and one of which was a serogroup B case. The case fatality rate for this period is 12.5%.

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).


Vaccine information


Vaccine uptake statistics

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