June 2008

Meningococcal meningitis

Introduction

Epidemiology

Risk for travellers

Transmission

Signs and symptoms

Treatment

Prevention

Vaccine information

References

Reading list

Links

Introduction

Meningococcal meningitis is caused by a gram negative bacterium, Neisseria meningitidis. There are 13 serotypes of N. meningitidis although only five serotypes, A, B, C, W135 and Y, are clinically important. Serotypes A, B and C are the most common causes of illness worldwide. W135 has emerged in recent years in Africa and the Middle East.

Epidemiology

Global epidemiology

Meningococcal disease occurs sporadically all over the world with seasonal variations [1]. N. meningitidis serogroups B and C are the most common cause of disease in Europe, the Americas, Australia, and New Zealand and tend to occur more frequently in winter and spring; serogroup A is the main cause of disease in Africa and Asia. 

The highest burden of meningococcal disease occurs in the ‘African meningitis belt’, which extends across the dry, savannah parts of sub-Saharan Africa from Senegal in the west, to Ethiopia in the east. During epidemics this region can have a disease incidence rate of >1,000 cases per 10,000 population [2]. Between 1 January and 10 February 2008, 2,312 cases of meningitis occurred in the meningitis belt [3]. These figures are 29% lower than those reported during the same period of 2007. In 2002, countries further south of the belt in the Great Lakes region, such as Tanzania, Rwanda, Burundi and the Democratic Republic of Congo reported over 2,200 cases of meningococcal disease, including 200 deaths; small villages and refugee camps were most affected [4].   

The largest recorded outbreak of meningococcal disease in history occurred in Africa in 1996 where 250,000 cases including 25,000 deaths were reported to the World Health Organization (WHO) [1].

Epidemics in meningitis belt countries occur in cycles, usually in the dry season. The dry season in west Africa is usually between November and May/June, although it may vary from year to year; in east Africa the seasons are variable. The serogroups most commonly associated with the African meningitis belt are A and C, however, serogroup W135 was isolated in Burkina Faso in 2000 [5] and has been isolated (along with A) from cases annually since 2002. During the 2002 outbreak in Burkina Faso, W135 strains of N. meningitidis were responsible for 80 percent of cases [5].

Serogroup A was responsible for two pandemics in Asia throughout the 1960s, 70s and 80s. It spread from China in the early 1980s to Nepal and India, and in 1987, serogroup A was responsible for an outbreak involving 2,000 pilgrims to the Hajj in Mecca, Saudi Arabia [6]. Carrier rates of meningococci can be as high as 80% in situations of overcrowding such as during the Hajj [7]. Subsequent outbreaks occurred among pilgrims on return to their home countries; this led to the introduction of a bivalent polysaccharide vaccine (against A and C serogroups) in 1988 as an entry requirement for Hajj and Umrah.

In 2000, an international outbreak of meningococcal infection due to serogroup W135 was associated with the Hajj pilgrimage. More than 330 cases in pilgrims or contacts of pilgrims in 12 countries were reported to the WHO between 28 February 2000 and 26 May 2000 [8]. The quadrivalent (A, C, W135, Y) vaccine was recommended for pilgrims to the Hajj in 2001 but uptake was not 100%, and cases of W135 associated with the Hajj occurred again in 2001 [9]. Quadrivalent vaccine was therefore made an entry requirement for all pilgrims to the Hajj and Umrah from 2002 and is now the only meningococcal vaccine available for travellers from the UK.

Current outbreaks of meningococcal disease are recorded in the NaTHNaC Outbreak Surveillance Database.

Meningococcal disease in travellers from England, Wales and Northern Ireland

In England, Wales and Northern Ireland, there is currently no routine reporting of travel-related meningococcal infections. Between 1998 and 2003, the most recent period for which data is available, there were 29 laboratory confirmed cases of meningitis associated with overseas travel. Of these, fifteen were serogrouped; serogroup C was the most frequent. The majority of cases (24/28) were associated with travel to Spain [10].

Classifying a case of meningococcal disease as being travel related is difficult: a traveller can have nasopharyngeal colonisation with meningococcal bacteria when they travel and develop disease while away, rather than picking up the infection in another country. A link with travel can be inferred when a strain of N. meningitidis is isolated that is rarely seen in the UK such as strains of serogroup A or W135 [11]. More information on which strains occur in the UK can be found on the Health Protection Agency website.

Risk for travellers

Meningococcal disease occurs in all countries of the world. Most travellers will be at a similar risk to infection during travel as they would be in the UK. A retrospective questionnaire study in 1994 identified 13 cases of meningococcal disease among travellers from industrialised countries [12]. The overall incidence was estimated to be 0.4 per 100,000 travellers per month.

Transmission of meningococcal disease is via droplet infection, and the risk is increased in overcrowded conditions. Travellers at higher risk include those living or working with local people (including health care workers), especially for prolonged periods, in endemic areas or where outbreaks are occurring (e.g. the African meningitis belt). A statement on risk for each country can be found on the NaTHNaC Country Information Pages.

Transmission

The reservoir for N. meningitidis is exclusively human, with the bacteria carried in the nasopharynx. Transmission occurs via the respiratory route from coughing and sneezing, and is acquired from a carrier during close contact. Most epidemics occur during the winter-spring period in temperate areas and during the dry season in tropical areas. In the meningitis belt of sub-Saharan Africa, the highest transmission period in west Africa is between November to May/June, with seasons being variable in east Africa.

Signs and symptoms

Meningococcal meningitis usually has a sudden onset with symptoms of fever, intense headache, nausea and vomiting. These symptoms can develop within minutes or hours. The patient is often irritable and prefers to lie still. Neck stiffness from meningeal irritation is characteristic.

A non-blanching petechial or purpuric rash often occurs with septicaemia, and delirium, coma and shock can ensue.  With early diagnosis and treatment the case fatality rate varies between 9% and 12% [12].

Treatment

Meningococcal infection is a medical emergency. On admission to hospital, treatment with parenteral antibiotics should be commenced immediately. Intensive care, monitoring and supportive treatment are required.

Prevention

A conjugated meningococcal type C vaccine is a routine vaccination in the UK and is offered to all children. The schedule consists of a single dose given at three and four months of age, with a third dose combined with Haemophilus influenzae type b (Hib) at 12 months of age.

Travellers should be advised on the mode of transmission and to avoid overcrowded situations.

A quadrivalent vaccine should be given to travellers to areas that are considered a risk for transmission.

Vaccine information

Conjugate meningitis C vaccine forms part of the UK immunisation schedule. Further information can be found in the Department of Health Immunisation against infectious disease (the ‘Green Book’)

The following section only refers to the quadrivalent ACW135Y polysaccharide vaccine. A conjugated ACW135Y vaccine is not available in the UK.

Indications for use of vaccine

• Travellers visiting areas at risk of meningococcal disease whose planned activities put them at higher risk including healthcare workers, those visiting friends and relatives and long-term travellers who have close contact with the local population.
• All travellers to Saudi Arabia for the purposes of Hajj or Umrah are required to show proof of vaccination.

Vaccine recommendations for specific countries can be found on the NaTHNaC Country Information Pages.

The Summary of Product Characteristics (SmPC) for the individual vaccine should be consulted for specific information relating to the product [13].

Vaccine schedule

Vaccine	Manufacturer	Schedule	Length of protection	Age range
ACWY Vax	GlaxoSmithKline	Children over two years and adults – single dose. Children over three months and under two years – 2 doses at an interval of three months.	5 years. Children who were under five years old when first vaccinated should receive a booster dose at 2-3 years if they remain at risk.	Adults and children over 3 months of age.

Contraindications

Confirmed anaphylactic reaction to a previous dose of vaccine, or to any constituent of the vaccine

References

1. World Health Organization.  Meningitis Fact sheet N 141.  Revised May 2003. [Accessed 25 June 2008]. Available at: http://www.who.int/mediacentre/factsheets/2003/fs141/en/. 

2. Committee to Advise on Tropical Medicine (CATMAT). Statement on meningococcal vaccination for travellers 1999; vol.25 [Accessed 25 June 2008] Available at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/99vol25/25sup/acs5.html

3. World Health Organization. Meningococcal disease in the African meningitis belt. Wkly Epidemiol Rec 2008;83:90-1.

World Health Organization.  Meningococcal disease in the Great Lakes area (Burundi, Rwanda, United Republic of Tanzania) Disease Outbreak News.  23 August 2002. [Accessed 25 June 2008]. Available at: http://www.who.int/csr/don/2002_08_23a/en/index.html. 

4. Teyssou R, Muros-Le Rouzic E. Meningitis epidemics in Africa: A brief overview. Vaccine 2007; 25 Suppl 1:A3-7.

5. Wilder-Smith A, Memish Z.  Meningococcal disease and travel.  Int J Antimicrob Agents 2003;21:102-6.

6. Al-Gahtani YM, El Bushra HE, Al-Qarawi SM, Al-Zubaidi AA, Fontaine RE.  Epidemiological investigation of an outbreak of meningococcal meningitis in Makkah (Mecca), Saudi Arabia, 1992.  Epidemiol Infect 1995: 115: 399-409.

7. Anon.  Meningococcal disease, serogroup W135.  Wkly Epidemiol Rec 2000:75;180.

8. Anon.  Meningococcal disease, serogroup W135.  Wkly Epidemiol Rec 2001:76;141-2.

9. Health Protection Agency. Illness in England, Wales, and Northern Ireland associated with foreign travel – a baseline report to 2002. London: Health Protection Agency Communicable Disease Surveillance Centre; 2004.

10. Health Protection Agency. Foreign travel-associated illness, England, Wales, and Northern Ireland – annual report 2005. London, Health Protection Agency: 2005. Available at http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/

HPAweb_C/1202487126306?p=1158945066450.

11. Koch S, Steffen R. Meningococcal disease in travelers: Vaccination recommendations. J Travel Med. 1994; 1; 4-7.

12. Rosenstein NE, Perkins BA, Stephens DS et al. Meningococcal disease. N Engl J Med 2001;344:1378-88.

13. GlaxoSmithKline. Summary of product characteristics for ACWY Vax last updated December 2005. [Accessed 25 June 2008]. Available online at http://emc.medicines.org.uk/emc/assets/c/html/displayDoc

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Reading list

Wilder-Smith A. Meningococcal disease: Risk for international travellers and vaccine strategies. Trav Med Infect Dis 2008;9:182-6

Links

NaTHNaC Guidelines for Hajj pilgrims

Department of Health meningitis information