Research and analysis

Laboratory confirmed cases of invasive meningococcal infection in England: October to December 2020

Updated 25 January 2022

Applies to England

In England, the national Public Health England (PHE) Meningococcal Reference Unit (MRU) confirmed 19 cases of invasive meningococcal disease (IMD) between October and December 2020. IMD cases were 90% lower during these 3 months compared to 184 cases in the equivalent period in 2019 (table 1). This low number of confirmed cases was observed across all capsular groups.

The COVID-19 pandemic and the implementation of social distancing measures and lockdown across the UK from 23 March 2020 has had a significant impact on the spread and detection of other infections, including IMD.

The age distribution of meningococcal capsular groups causing IMD is summarised in table 2, with capsular group B (MenB) accounting for 74% (14 out of 19) of all cases, followed by meningococcal W (MenW) (n=3, 16%), and meningococcal C (MenC) n=1, 5%).

There were 14 MenB cases confirmed between October and December 2020, 88% lower than the equivalent period in 2019 (114 cases). MenW cases were 92% lower (3 cases) than the number of cases confirmed in the same time period in 2019 (37 cases). In this quarter, 1 case was confirmed with MenC disease in 2020 compared to 9 cases in the equivalent period in 2019 (37 cases). There were no MenY cases confirmed in this period in 2020, compared to 20 cases the previous year (table 1). One confirmed case of ungrouped or ungroupable capsular group was reported in this quarter. There were no reported cases for capsular groups A, X or Z/E during the reporting period.

Between October and December 2020, MenB was responsible for the majority of IMD cases in children aged less than 5 years of age (89%, 8 out of 9), with 1 confirmed case of MenW.

MenB also accounted for 63% of cases in individuals aged between 5 and 64 years and 50% of cases in adults aged 65 years or more (table 2).

The introduction of a routine national MenB immunisation programme for infants was announced in June 2015, with immunisation of infants starting from 1 September 2015.

Vaccine coverage estimates for infant MenB immunisation across England was 92.5% for 2 doses at 12 months of age and 89.5% for the booster dose by 24 months old (evaluated between July to September 2020). The 2-dose infant MenB schedule has been shown to be highly effective in preventing MenB disease in infants.

Of the 3 MenW cases confirmed between October and December 2020, there was:

• 1 case in a child aged between 1 and 4 years old
• 1 case in an adult aged between 25 and 44 years
• 1 case in an adult aged 65 years or older

There were no confirmed cases in children and young people aged between 5 and 24 years old.

The earlier increase in MenW cases, which has been previously reported, led to the introduction of MenACWY conjugate vaccine to the national immunisation programme in England (see Meningococcal ACWY conjugate vaccination and Meningococcal ACWY vaccination programme).

The targeted catch-up with MenACWY vaccine began in August 2015, at which time it also replaced the existing time-limited MenC ‘freshers’ vaccination programme. The 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 the first cohorts to be routinely offered MenACWY vaccine in schools from September 2015 and evaluated up to the end August 2019 was:

• 88.0% – year 9 in 2018 to 2019
• 86.7% – year 10

The impact of the MenACWY teenage and the MenB infant vaccination programmes continues to be monitored. Early assessment of the infant MenB programme and MenACWY vaccination in the 2015 school leaver cohort have been published.

All teenage cohorts remain eligible for opportunistic MenACWY vaccination until their 25th birthday and it is important that these young people continue to be encouraged to be immunised, particularly if they are entering higher education institutions.

Table 1: Invasive meningococcal disease in England by capsular group and laboratory testing method: October to December 2019 and 2020

Capsular groups*	Culture and PCR (2019)	Culture and PCR (2020)	Culture only (2019)	Culture only (2020)	PCR only (2019)	PCR only (2020)	Total (2019)	Total (2020)
B	23	3	30	5	61	6	114	14
C	1	0	6	1	2	0	9	1
W	7	0	25	3	5	0	37	3
Y	6	0	10	0	4	0	20	0
Other**	0	0	2	1	2	0	4	1
Total	37	3	73	10	74	6	184	19

*No cases of group A, X or Z were confirmed during the periods summarised in the table.

**‘Other’ includes group E and ungrouped or 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).

Table 2. Invasive meningococcal disease in England by capsular group* and age group at diagnosis: October to December 2020

Age groups	Capsular group B	Capsular group C	Capsular group W	Other**	Total number	Total percentage
<1 year	5	0	0	0	5	26.3%
1 to 4 years	3	0	1	0	4	21.1%
5 to 9 years	2	0	0	0	2	10.5%
10 to 14 years	0	1	0	0	1	5.3%
15 to 19 years	1	0	0	1	2	10.5%
20 to 24 years	0	0	0	0	0	–
25 to 44 years	0	0	1	0	1	5.3%
45 to 64 years	2	0	0	0	2	10.5%
65+ years	1	0	1	0	2	10.5%
Total	14	1	3	1	19	–

*No cases of group Y, A, X or Z/E were confirmed during the periods summarised in the table.

**‘Other’ includes ungrouped or 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).