Research and analysis

Invasive meningococcal disease in England: annual laboratory confirmed reports for epidemiological year 2021 to 2022

Updated 1 June 2023

Applies to England

Laboratory confirmations

This report presents data on laboratory-confirmed invasive meningococcal disease (IMD) for the last complete epidemiological year, 2021 to 2022. Epidemiological years run from week 27 in one year (beginning of July) to week 26 the following year (end of June) ^{[footnote 1]}.

In England, the national UK Health Security Agency (UKHSA) Meningococcal Reference Unit (MRU) confirmed 205 cases of IMD during 2021 to 2022 compared to the exceptionally low number of 80 cases reported in 2020 to 2021 when coronavirus (COVID-19) pandemic restrictions were in place (Table 1). IMD cases had fallen by 83% in 2020 to 2021 compared to 463 confirmed cases in 2019 to 2020 and 531 confirmed cases in 2018 to 2019 (Figure 1).

The COVID-19 pandemic and the implementation of social distancing measures and lockdown periods across the UK have had a significant impact on the spread and detection of other infections including IMD (1). From July 2021 COVID-19 containment measures were withdrawn in England and overall case numbers have increased.

In England, there has been a marked overall decline in confirmed IMD cases over the last 2 decades from a peak of 2,595 cases in 1999 to 2000. The initial decline in IMD cases was driven by the introduction of vaccination against group C (MenC) disease in 1999 which reduced MenC cases by approximately 96% (to around 30 to 40 cases each year). Total IMD has continued to decrease from 2 per 100,000 in 2006 to 2007 to 1 per 100,000 since 2011 to 2012; this latter decline was mainly due to secular changes in group B (MenB) cases before the introduction of the MenB infant and meningococcal A, C, W and Y (MenACWY) teenage vaccination programmes in 2015. IMD incidence is currently below 1 per 100,000 (Figure 2) (2).

The distribution of IMD cases by capsular group in 2021 to 2022 is summarised in Table 1, with MenB accounting for 87% (179 out of 205) of all cases, followed by MenW (n=13, 6%), and MenY (n=2). One case each of MenC, MenA and MenE were reported and 8 ungrouped or ungroupable.

In 2021 to 2022, 179 individuals were confirmed with MenB, compared to 61 cases in 2020 to 2021 and 307 in 2019 to 2020. MenB was responsible for the majority of IMD cases in individuals under 25 years of age: infants (100%; 34 cases), 1 to 4 year-olds (89%; 16 out of 18) and 5 to 14 year-olds (100%; 8 cases).

In 2021 to 2022 MenB also contributed to the highest proportion (67%; 37 out of 55) of cases in individuals aged 25 years and over (Table 2) similar to 2020 to 2021 (66%; 21 out of 32) contrary to earlier years – when MenB accounted for 45% (99 out of 218) of all cases in this age group in 2019 to 2020 and 36% (93 out of 259) in 2018 to 2019 – as disease covered by MenACWY vaccine was markedly reduced and has remained very low following the impact of measures taken to help control the COVID-19 pandemic.

There were 13 MenW cases in 2021 to 2022 compared to 5 cases in 2020 to 2021. MenW cases in 2021 to 2022 were 83% lower than in 2019 to 2020 when 78 cases were reported. Confirmed MenW cases have decreased over the last 5 years after peaking at 225 cases in 2016 to 2017.

MenC cases remained low, with one case reported in 2021 to 2022 and 5 in 2020 to 2021 compared to 27 cases in 2019 to 2020. Similarly MenY cases also remained low with 2 cases in 2021 to 2022 and 6 cases in 2020 to 2021 compared to 41 cases in 2019 to 2020 (Table 1).

Adults aged 25 years and older accounted for all MenC and MenY cases, 85% of MenW cases and 21% of MenB cases (Table 2).

Deaths

The provisional IMD case fatality ratio (CFR) in England was 6% (12 out of 205) during 2021 to 2022 based on Office for National (ONS) death registrations recording meningococcal disease as an underlying cause ^{[footnote 2]}

Vaccine coverage

Infants in the UK were offered routine MenB immunisation with 4CMenB from 1 September 2015 (3). In England, the latest annual vaccine coverage estimates (1 April 2021 to 31 March 2022) for infants eligible for 4CMenB were 91.5% for 2 doses by 12 months of age and 88.0% for the one-year by 24 months of age (4). The schedule has been shown to be highly effective in preventing MenB disease in infants and toddlers (5).

The previously reported increase in MenW cases (6,7) led to the introduction of MenACWY conjugate vaccine to the national immunisation programme in England (8). Targeted catch-up with MenACWY vaccine began in August 2015 at which time it also replaced the existing time-limited MenC ‘freshers’ vaccination programme. MenC vaccine was also directly substituted with MenACWY vaccine in the routine adolescent school programme (school year 9 or 10) from autumn 2015.

Coverage for young people routinely offered MenACWY vaccine in the 2020 to 2021 school year (end August 2021) was 76.5% (year 9) and 80.9% (year 10) (9). Local arrangements are ongoing to allow cohorts who missed school vaccinations when COVID-19 restrictions were in place to catch up.

The MenACWY teenage vaccination programme has led to large reductions in IMD due to the respective serogroups across all age groups through a combination of direct and indirect (herd) protection (10).

All teenage cohorts remain eligible for opportunistic MenACWY vaccination until their 25th birthday and it is important that these cohorts continue to be encouraged to be immunised, particularly if they are entering higher educations institutions where their risk of disease is much higher than that of their peers (11).

There are useful resources available free of charge from UKHSA and from meningitis charities to support messaging on the importance of vaccination, being aware of signs and symptoms of meningitis and septicaemia and seeking early clinical help.

Table 1. Invasive meningococcal disease in England by capsular group and laboratory testing method: 2020 to 2021 and 2021 to 2022

Capsular groups*	Culture and PCR (2020/21)	Culture and PCR (2021/22)	Culture only (2020/21)	Culture only (2021/22)	PCR only (2020/21)	PCR only (2021/22)	Total (2020/21	Total (2021/22)
A	0	0	0	0	0	1	0	1
B	12	40	18	49	31	90	61	179
C	0	0	3	1	2	0	5	1
E	0	1	0	0	0	0	0	1
W	0	1	3	10	2	2	5	13
Y	1	0	4	1	1	1	6	2
Ungrouped/ungroupable**	0	0	2	3	1	5	3	8
Total	13	42	30	64	37	99	80	205

*No cases of group X or Z were confirmed during the period covered by the table.

**‘Ungroupable’ refers to invasive clinical meningococcal isolates that were non-groupable, while ‘ungrouped’ cases refer to culture-negative but PCR screen (ctrA) positive and negative for the 4 genogroups (B, C, W and Y) routinely tested for.

Figure 1. Invasive meningococcal disease in England by capsular group: 2012 to 2013 through to 2021 to 2022

*Other includes capsular groups: X, E, ungrouped and ungroupable. Ungroupable refers to invasive clinical meningococcal isolates that were non-groupable, while ungrouped cases refers to culture-negative but PCR screen (ctrA) positive and negative for the 4 genogroups [B, C, W and Y] routinely tested for.

Figure 2. Incidence of invasive meningococcal disease in England: 2012 to 2013 through to 2021 to 2022

Table 2. Invasive meningococcal disease in England by capsular group and age group at diagnosis: 2021 to 2022

Age groups	Capsular group B (%)	Capsular group C (%)	Capsular group W (%)	Capsular group Y (%)	Capsular group Other* (%)	Annual total (%)
<1 year	34 (19)	0 (–)	0 (–)	0 (–)	0 (–)	34 (17)
1 to 4 years	16 (9)	0 (–)	0 (–)	0 (–)	0 (–)	18 (9)
5 to 9 years	3 (2)	0 (–)	0 (–)	0 (–)	0 (–)	3 (1)
10 to 14 years	5 (3)	0 (–)	0 (–)	0 (–)	0 (–)	5 (2)
15 to 19 years	64 (36)	0 (–)	0 (–)	0 (–)	4 (40)	68 (33)
20 to 24 years	20 (11)	0 (–)	2 (15)	0 (–)	0 (–)	22 (11)
25 to 44 years	10 (6)	0 (–)	2 (15)	1 (50)	3 (30)	16 (8)
45 to 64 years	16 (9)	1 (100)	2 (15)	0 (–)	0 (–)	19 (9)
65+ years	11 (6)	0 (–)	7 (54)	1 (50)	1 (10)	20 (10)
Total	179 (–)	1 (–)	13 (–)	2 (–)	10 (–)	205 (–)

*‘Other’ includes group A, X, E, ungrouped and ungroupable. ‘Ungroupable’ refers to invasive clinical meningococcal isolates that were non-groupable, while ‘ungrouped’ cases refer to culture-negative but PCR screen (ctrA) positive and negative for the 4 genogroups (B, C, W and Y) routinely tested for.

References

1. Subbarao S and others (2021). ‘Invasive meningococcal disease, 2011 to 2020, and impact of the COVID-19 pandemic, England.’ Emerging Infectious Diseases: volume 27 number 6

2. Office of National Statistics. Mid-year 2021 population estimates

3. Public Health England and NHS England (22 June 2015). ‘Introduction of Men B immunisation for infants.’ (Bipartite letter)

4. Public Health England and NHS Digital (29 September 2022). ‘Childhood vaccination coverage statistics – England 2020 to 2021’

5. Ladhani S and others (2020). ‘Vaccination of Infants with Meningococcal Group B Vaccine (4CMenB) in England.’ New England Journal of Medicine: volume 382 number 4

6. Public Health England (2015). ‘Continuing increase in meningococcal group W (MenW) disease in England.’ Health Protection Report: volume 9, number 7 (news)

7. Public Health England. ‘Freshers told ‘it’s not too late’ for meningitis C vaccine.’ Press release: 27 November 2014

8. Public Health England and NHS England (22 June 2015). ‘Meningococcal ACWY conjugate vaccination (MenACWY).’ (Bipartite letter)

9. UKHSA (2022). ‘Meningococcal ACWY (MenACWY) vaccine coverage for the NHS adolescent vaccination programme in England, academic year 2020 to 2021.’ Health Protection Report: volume 16, number 2 (8 February)

10. Campbell H and others (2022). ‘Impact of an adolescent meningococcal ACWY immunisation programme to control a national outbreak of group W meningococcal disease in England: a national surveillance and modelling study for teenagers to control group W meningococcal diseases, England, 2015 to 2016.’ Lancet Child Adolescent Health: volume 6 issue 2

11. Mandal S and others (2017). ‘Risk of invasive meningococcal disease in university students in England and optimal strategies for protection using MenACWY vaccine.’ Vaccine: volume 35 issue 43

1. When most cases of a disease arise in the winter months, as for IMD, epidemiological year is the most consistent way to present the data as the peak incidence may be reached before or after the year end. Using epidemiological year avoids the situations where a calendar year does not include the seasonal peak or where 2 seasonal peaks are captured in a single calendar year. ↩

2. Death data from the Office of National Statistics includes all deaths coded to meningitis or meningococcal infection as a cause of death and linked to a laboratory-confirmed case. ↩