We obtain data on the number of cases and incidence rates of bacterial meningitis and septicaemia from the Health Protection Agency, Health Protection Scotland, Health Protection Surveillance Centre (Republic of Ireland) and the Office of National Statistics. There are several methods of data recording: Laboratory confirmed, Notifications and Enhanced Surveillance.
Laboratory confirmed cases are data obtained from microbiology labs that have analysed blood or CSF samples from patients suspected of meningitis or septicaemia. These data inform us of the type of meningitis or septicaemia (ie meningococcal, pneumococcal) and the serogroup (e.g. meningococcal group B or group C).Notified cases are data obtained from medical doctors who clinically diagnose meningococcal disease, or any form of meningitis. They have a legal obligation to report these cases to Consultant Communicable Disease Control. These notified figures can only provide us with the type of meningitis or septicaemia and not the serogroup.
Both laboratory confirmed and notifications data, however, are underestimates of the total case numbers of meningococcal meningitis and septicaemia due to underreporting. Enhanced surveillance of Meningococcal Disease (ESMD) was set up to provide a more realistic estimate of the number of cases of meningococcal disease. The aim was to improve the ascertainment of these diseases by taking into account both laboratory confirmed data, notifications and reconcile them with data from the Meningococcal Reference Unit (Manchester). At present, enhanced surveillance figures are only available for meningococcal disease. In fact the data collected through ESMD are not entirely accurate and may overestimate cases, but together the three systems provide a more complete picture of disease levels and trends.
Notified cases of meningococcal septicaemia and bacterial meningitis in England and Wales by year
|
|
Year
|
|
Disease
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
2005
|
|
Meningococcal
septicaemia
|
1822
|
1614
|
1238
|
842
|
732
|
691
|
721
|
|
Meningococcal
meningitis
|
1145
|
1164
|
1020
|
706
|
646
|
554
|
579
|
|
Pneumococcal
meningitis
|
237
|
218
|
202
|
166
|
205
|
177
|
220
|
|
TB meningitis
|
122
|
94
|
161
|
140
|
150
|
140
|
228
|
|
Haemophilus
Influenzae
meningitis
|
29
|
39
|
73
|
62
|
63
|
45
|
44
|
|
Other specified
|
194
|
189
|
191
|
148
|
115
|
114
|
110
|
|
Unspecified
|
278
|
275
|
326
|
213
|
208
|
180
|
205
|
|
Total
|
3827
|
3593
|
3211
|
2277
|
2119
|
1901
|
2107
|
Source: HPA Centre of Infections
- In England and Wales from 1999 to 2005 there was a 45% decrease in the total number of meningococcal septicaemia and bacterial meningitis cases – mainly due to the drop in group C meningococcal disease following introduction of MenC vaccine
- Meningococcal infection has remained the leading cause of bacterial meningitis, followed by pneumococcal
- Between 1999-2001 there was a steady increase in the number of Hi meningitis cases, however this began to decline from 2003 when the Hib booster campaign was introduced in the UK to reduce this resurgence
- TB meningitis has increased in case numbers since 2000 and is at its highest level in 2005, this is likely to be due to a global increase in TB in recent years
- Over the period 1999-2005, the drop in meningococcal septicaemia has been more marked than meningococcal meningitis. This is consistent with the effect of MenC vaccine, since the mid 1990’s group C meningococcal infection caused more severe cases (i.e. septicaemia) than group B
Age-specific incidence of meningococcal septicaemia and bacterial meningitis in England and Wales - 2005
|
|
Incidence by age group (per 100,000 population)
|
|
Disease
|
0-4
|
5-9
|
10-14
|
15-24
|
25-44
|
45-64
|
65+
|
|
Meningococcal septicaemia
|
13.8
|
2.4
|
1.3
|
1.1
|
0.2
|
0.2
|
0.4
|
|
Meningococcal meningitis
|
9.2
|
1.3
|
0.8
|
1.5
|
0.5
|
0.3
|
0.4
|
|
Pneumococcal meningitis
|
3.1
|
0.3
|
0.2
|
0.1
|
0.2
|
0.3
|
0.4
|
|
TB meningitis
|
0.4
|
0.1
|
0.1
|
0.3
|
0.6
|
0.4
|
0.4
|
|
Haemophilus influenzae meningitis
|
0.8
|
0.1
|
0.1
|
0.0
|
0.0
|
0.0
|
0.0
|
|
Other specified
|
1.4
|
0.1
|
0.0
|
0.4
|
0.1
|
0.1
|
0.1
|
|
Unspecified
|
2.7
|
0.6
|
0.2
|
0.6
|
0.2
|
0.1
|
0.2
|
|
Total
|
31.3
|
4.8
|
2.7
|
4.0
|
1.9
|
1.5
|
1.9
|
Source: HPA Centre for Infections
- Babies and young children, 0-4 years old, have the highest risk of meningococcal infection and all forms of bacterial meningitis
- An additional age group at high risk of meningococcal infection are the 15-24 year olds
- In children less than 15 years of age, most meningococcal infection is notified as septicaemia. In adolescents and adults, meningococcal meningitis appears to be more common than septicaemia
Number of cases and incidence rate of meningococcal infection in the UK and Republic of Ireland during 2004
|
Country
|
Cases of
Meningococcal Disease
|
Population
size
|
Rate per
100,000
|
|
Scotland
|
152
|
5062011
|
3.0
|
|
England
|
1981
|
49138831
|
4.0
|
|
Wales
|
112
|
2903085
|
3.9
|
|
Northern
Ireland
|
107
|
1685267
|
6.3
|
|
Rep. of Ireland
|
201
|
3917200
|
5.1
|
Sources: Health Protection Agency, Health Protection Scotland, Health Protection Surveillance Centre (Ireland) and the Office of National Statistics
- England has the highest number of cases because its population is the largest
- The disease rate per head of population is higher on the island of Ireland than in Northern Ireland than in Scotland, Wales or England
NB. These figures are based on enhanced surveillance data where available. Enhanced surveillance data are not collected in Scotland, which probably explains the apparent lower disease rate.
Lab confirmed data shown below, based on blood or CSF samples analysed from patients suspected of meningitis and septicaemia, provides a breakdown of meningococcal groups. This information cannot be provided by notification data, and so lab confirmed data has been used to show comparisons between number of cases of each meningococcal group. Enhanced surveillance can only provide a breakdown of figures for groups B and C and therefore are inadequate for these purposes.
Lab confirmed cases of meningococcal infection by year and serogroup in England and Wales
|
|
Year
|
|
Serogroup
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
2005
|
|
B
|
1480
|
1645
|
1695
|
1334
|
1362
|
1134
|
1166
|
|
C
|
996
|
712
|
322
|
162
|
99
|
58
|
25
|
|
W135
|
51
|
109
|
135
|
81
|
42
|
34
|
28
|
|
Y
|
19
|
29
|
31
|
25
|
20
|
28
|
36
|
|
Others (A, X, Y,
29E)
|
7
|
6
|
9
|
4
|
6
|
7
|
2
|
|
Ungroupable
|
20
|
22
|
9
|
2
|
3
|
1
|
–
|
|
Ungrouped
|
258
|
137
|
139
|
110
|
76
|
52
|
46
|
|
Total
|
2831
|
2660
|
2340
|
1718
|
1608
|
1314
|
1303
|
Source: Health Protection Agency
- Meningococcal group B remains the main cause of meningococcal infection in England and Wales
- Between 1999 and 2005 there was a steady decline in the total number of cases of meningococcal disease
- The proportion of disease due to meningococcal group C has declined since 1999. This reduction is attributed to the success of the Men C vaccination introduced in 1999/2000. This vaccine is unable to control the number of cases of group B infection, which has shown a coincidental fall from 2001-2005
- An outbreak of W135 meningococcal infection occurred amongst pilgrims on Hajj in 2000. Cases associated with those returning from Hajj were reported in many countries including the UK. So, the increase of case numbers of W135 from 1999 – 2001 can be attributed to this outbreak
Enhanced surveillance is shown below to provide a more realistic picture of meningococcal disease cases. Lab confirmed data and notifications probably underestimate the number of cases. However, enhanced surveillance may over estimate the actual number.
Cases of meningococcal infection in England and Wales by year (2002-2005)
|
|
Year
|
|
Serogroup
|
2002
|
2003
|
2004
|
2005
|
|
B
|
1085
|
1019
|
847
|
1017
|
|
C
|
126
|
65
|
51
|
21
|
|
Other
|
147
|
75
|
76
|
94
|
|
Unconfirmed
|
1326
|
1281
|
1119
|
1212
|
|
Total
|
2684
|
2440
|
2093
|
2344
|
Source: Health Protection Agency
- Compared with enhanced surveillance data, lab confirmed data (Figure 4) underestimate the number of cases of meningococcal infection by around 1.5 fold
- From Figure 4 it can be seen that the main impact of MenC vaccine in reducing cases of group C disease had already occurred before 2002. This graph shows that group C disease continues to dwindle (2002-2005) due to the vaccine, and shows a coincidental decline of group B cases.
Lab confirmed cases of meningococcal infection in Scotland by serogroup and year
|
|
Year
|
|
Serogroup
|
2000
|
2001
|
2002
|
2003
|
2004
|
|
B
|
138
|
106
|
63
|
78
|
68
|
|
C
|
67
|
25
|
9
|
3
|
5
|
|
Y
|
6
|
1
|
4
|
1
|
5
|
|
W135
|
5
|
5
|
3
|
4
|
4
|
|
Ungroupable
and unknown
|
72
|
7
|
3
|
4
|
70
|
|
Total
|
288
|
144
|
82
|
90
|
152
|
Source: Health Protection Scotland
- Group B has been the major cause of meningococcal infection in Scotland and since 2000 has declined in cases numbers
- Cases of group C meningococcal infection have declined from 2000-2004, due to the MenC vaccine introduction in 1999/2000.
Meningococcal infection cases from 2002-2005 in Northern Ireland by serogroup
|
|
Year
|
|
Serogroup
|
2002
|
2003
|
2004
|
2005
|
|
B
|
61
|
61
|
54
|
56
|
|
C
|
7
|
3
|
2
|
0
|
|
Other
|
3
|
3
|
13
|
1
|
|
Unconfirmed
|
35
|
30
|
38
|
37
|
|
Total
|
106
|
100
|
107
|
94
|
Source: Health Protection Agency
- In general, the total number of meningococcal infection cases has remained relatively similar from 2002-2005
- Group B is the major cause of meningococcal infection
- Similar to other parts of the UK, Northern Ireland has seen a decline in meningococcal infection with time (2002-2005) due to the effect of MenC vaccine
Meningococcal infection cases by serogroup and year in the Republic of Ireland
|
|
Year
|
|
Serogroup
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
2005*
|
|
B
|
292
|
258
|
245
|
199
|
206
|
163
|
168
|
|
C
|
135
|
139
|
35
|
14
|
5
|
5
|
5
|
|
W135
|
4
|
3
|
3
|
6
|
3
|
1
|
3
|
|
Y
|
2
|
4
|
1
|
2
|
2
|
2
|
3
|
|
Non-groupable
|
12
|
6
|
7
|
1
|
4
|
1
|
0
|
|
Unconfirmed
|
91
|
105
|
39
|
31
|
17
|
26
|
26
|
|
Total
|
536
|
515
|
330
|
253
|
237
|
198
|
205
|
Source: Health Protection Surveillance Centre, Ireland
*2005 figures are provisional data
- In Ireland over the period 1999-2005 the total number of meningococcal cases has decreased by over 61% and has remained steady over last two years
- The levels of group W135 and Y have remained fairly consistent over this time, whilst group C has notably declined by > 96% (1999-2005)
- A fall in group B cases has also occurred over 1999-2005, due to natural fluctuation
Bacterial meningitis cases in the Republic of Ireland by year
|
|
Year
|
|
Disease
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
2005*
|
|
Meningococcal
|
536
|
515
|
330
|
253
|
237
|
198
|
205
|
|
Pneumococcal
|
19
|
25
|
20
|
15
|
25
|
22
|
11
|
|
Haemophilus influenzae
|
2
|
6
|
2
|
3
|
7
|
4
|
9
|
|
Group B Streptococcus
|
4
|
3
|
3
|
2
|
2
|
6
|
4
|
|
Listeria
|
0
|
1
|
2
|
0
|
2
|
1
|
0
|
|
TB
|
7
|
2
|
2
|
3
|
5
|
6
|
8
|
|
Other
|
4
|
3
|
4
|
1
|
6
|
2
|
3
|
|
Unknown
|
15
|
31
|
33
|
20
|
27
|
28
|
21
|
|
Total
|
587
|
586
|
396
|
297
|
311
|
267
|
261
|
Source: Health Protection Surveillance Centre, Ireland
*2005 figures are provisional data
- As with England and Wales a similar trend is shown for the Republic of Ireland; the number of meningococcal disease cases has continued to fall since 1999. This fall is in part due to the introduction of the MenC vaccine
- Overall, the number of meningococcal meningitis cases far exceeds all other causes of bacterial meningitis even though cases of meningococcal meningitis has substantially declined from 1999-2005
- Cases of TB meningitis have shown an increase from 2000-2005 due to a global elevation in TB during these years
- Pneumococcal infection represents the second main cause of meningitis in the Republic of Ireland
Pneumococcal bacteria are responsible for several types of infectious disease these range in severity from invasive disease such as septicaemia, pneumonia and meningitis to less severe infection such as earache. In the UK (2005) invasive pneumococcal infections accounted for over 6287 cases, of these 252 were meningitis cases and are represented below by age.
Number of cases and Incidence of pneumococcal meningitis by age group in 2005
|
|
Lab confirmed
|
Notified
|
|
Age Group (years)
|
Incidence
(per 100,000 population)
|
Number of Cases
|
Number of Cases
|
|
0-4
|
3.0
|
94
|
95
|
|
5-9
|
0.3
|
9
|
10
|
|
10-14
|
0.1
|
4
|
7
|
|
15-44
|
0.2
|
45
|
37
|
|
45-64
|
0.4
|
52
|
38
|
|
65-74
|
0.8
|
35
|
33
|
|
75-79
|
0.5
|
8
|
|
80+
|
0.2
|
5
|
|
Total
|
5.5
|
252
|
220
|
Source: HPA - Centre of Infectious Diseases and the Office of National Statistics
- Young children aged 0-4 have the highest incidence and the highest number of cases of pneumococcal meningitis when compared to other age groups
- The second most vulnerable group to pneumococcal meningitis is the elderly (65-74)
- Compared with notifications data, above table, lab confirmed data shows higher total number of cases (252 vs 220 respectively)
- Two recent studies indicate that the cases identified by notification and lab-confirmation probably underestimate the true number of cases of invasive pneumococcal disease.1,2
References
1. McIntosh ED, Booy R. Invasive pneumococcal disease in England and Wales: what is the true burden and what is the potential for prevention using 7 valent pneumococcal conjugate vaccine? Arch Dis Child. 2002; 86(6):403-6.
2. McIntosh ED How many episodes of hospital care might be prevented by widespread uptake of pneumococcal conjugate vaccine? Arch Dis Child. 2003; 88(10):859-61.
Page last updated 26.09.07