West Midlands Key Health Data 2008/09
CHAPTER ELEVEN: MENINGOCOCCAL DISEASE IN THE WEST MIDLANDS: 1999-2008
Adedoyin Awofisayo, Helen Bagnall and Dr Babatunde Olowokure
Main Body
7: Environment And Health – Outdoor Air Pollution
9: Predictors Of Emergency Department Use At Neighbourhood Level In The West Midlands
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11.1 Introduction
The Regional Epidemiology Unit of the Health Protection Agency (West Midlands) collates and analyses data from the three local Health Protection Units and NHS Trust laboratories from across the region. In this chapter, data from the enhanced surveillance scheme for meningococcal disease will be used to identify trends and describe epidemiological patterns from 1999 to 2008.
The HPA West Midlands Enhanced Meningococcal Disease Surveillance system collects a wide range of information on patient risk factors, unlike the statutory Notification Of Infectious Diseases system (NOIDS), which only collects basic patient information.
Meningococcal disease which primarily consists of meningococcal meningitis and meningococcal septicaemia is a systemic infection caused by Neisseria meningitidis.
In England and Wales, meningococcal disease has been on a downward trend with about 120% fewer confirmed cases reported in 2008 (1262 cases) when compared with 1999 (2779 cases) 1.
A similar trend has been observed in the West Midlands with the highest number of cases reported in 1999 (250 confirmed cases at a rate of 4.7 per 100,000 population) and the least in 2008 (102 confirmed cases at a rate of 1.9 per 100,000 population) (Figure 11.1).
The incidence of meningococcal infection type B has consistently been higher than all the other types. Meningococcal type C has drastically decreased from 81 cases (32.4 per 100 population) in 1999 to just 2 cases (1.9 per 100 population) in 2008 (Figure 11.2). This is due to the phased introduction of the Meningococcal C (MenC) conjugate vaccine in 1999 in which the vaccine was offered to all children and adolescents 18 years and under 2. MenC vaccine is now part of the routine Childhood Immunisation Programme in the UK.
Overall, septicaemia accounted for approximately 50% of all confirmed meningococcal cases. However, in 2008, 33% of cases were septicaemia and 37% of cases were meningitis and about 15% were unknown. A clinical diagnosis of both septicaemia and meningitis has consistently accounted for less than 15% of all confirmed cases (Figure 11.3).
Figure 11.1 below shows the association between PbR expenditure and prevalence (accounting for 71% of the variation).
Figure 11.1: Notifications and incidence of meningococcal disease in West Midlands; 1999-2008
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Figure 11.2: Trend of meningococcal serotype in the West Midlands 1999-2008
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Figure 11.3: Clinical diagnosis of meningococcal disease in the West Midlands 1999 - 2008
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11.2 Age, Sex and Ethnicity
Ethnicity was known for about 58% of the cases, and of these, the white ethnic group accounted for 89% (830/932). The rate of infection is highest in the 0 - 14 years age group but is predominantly in infants (<1 year) and pre school (1-4 years) children (Figures 11.4 and 11.5). Although the incidence rate over the years is almost consistently higher in males, higher numbers of cases were reported in females in the age group 25 - 44 years and 65+ years (Figures 11.6 and 11.7).
Figure 11.4: Incidence of Meningococcal disease by age group (years) in the West Midlands 1999-2008
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Figure 11.5: Incidence of meningococcal disease in the 0-24 years age group in the West Midlands 1999-2008
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Figure 11.6: Directly age standardised incidence of meningococcal disease in the West Midlands 1999-2008
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Figure 11.7: Incidence of meningococcal disease by age and sex in the West Midlands 1999 - 2008
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11.3 Meningococcal Disease by Primary Care Trust
The rate of meningococcal disease decreased over the years in most PCTs but the decrease was significant in Dudley, North Staffordshire, Warwickshire and Wolverhampton (Table 11.1). .
Table 11.1: Incidence of Meningococcal disease by PCT in the West Midlands; 1999 and 2008
Source: HPA West Midlands Enhanced Meningococcal Disease Surveillance system | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Map 11.1: Incidence rate (per 100,000) of Meningococcal disease by PCT in the West Midlands; 1999- 2003*
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Map 11.2: Incidence rate (per 100,000) of Meningococcal disease by PCT in the West Midlands; 2004- 2008
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11.4 Seasonality
Meningococcal disease occurs mainly in the winter season. Its highest incidence is in January and then it gradually declines until it reaches its lowest point in September and then steadily increases through the winter (Figure 11.8). This pattern is seen through out the years 1999 - 2008.
Figure 11.8: Number of meningococcal cases by month in the West Midlands 1999-2008
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11.5 Case Fatality Rate
The case fatality rate of meningococcal disease does not seem to have a particular trend but was highest in 2001 (8.7% CFR) lowest in 2002 (2% CFR), and has slightly increased to 4.9% in 2008 from 2.7% in 2007 (Figure 11.9).
Figure 11.9: Confirmed cases and case fatality rate of meningococcal infections in the West Midlands 1999-2008
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11.6 Vaccination
Meningococcal C (MenC) Conjugate vaccine was introduced in 1999 and is now part of the routine childhood immunisation programme. Vaccine coverage has increased since its introduction and was approximately 96% in 2008. As vaccine coverage has increased, the rate of infection in the West Midlands has decreased, thus, a directly proportional relationship could be observed (Figure 11.10).
Figure 11.10: Percentage of children immunised by their 2nd birthday and rate of meningococcal infection in the West Midlands
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11.7 Meningococcal Disease and Deprivation
The proportion of infection of meningococcal disease was highest in the most deprived population and lowest in the least deprived population. A linear trend could be observed as proportion of infection increased with deprivation (IMD 2007) (Figure 11.11).
Figure 11.11: Proportion of meningococcal disease in the West Midlands according to deprivation; 1999-2008
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Reference:
- Health Protection Agency. Laboratory confirmed cases of all invasive meningococcal disease by age and epidemiological year, England and Wales 1998-99 to 2007-08. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1234510032217?p=1201094595391 (Accessed March 2009)
- Department of Health. Meningitis C. Available at: http://www.dh.gov.uk/en/Publichealth/Communicablediseases/MeningitisC/DH_207 (Accessed March 2009)
For more information please contact Sarafina
Cotterill
© Public Health, Epidemiology and Biostatistics Unit, School of Health and Population Sciences, University of Birmingham