Meningococcal

Meningococcal disease is caused by the bacteria Neisseria meningitidis, of which there are 13 known serogroups. The most common are A, B, C, W and Y. The bacteria lives in the human nasopharynx and is transmitted through person-to-person contact (kissing, sharing cigarettes, drinking glasses) through secretions of the respiratory tract or saliva.

Up to 5 to 25% of the population may be carriers of the disease in endemic situations. Carrier prevalence has been found to be highest in situations of crowding. Institutional situations are deemed to have higher risk (military bases, student dormitories, universities, and youth camps).

Meningococcal disease is endemic in certain regions of the world such as sub-Saharan Africa and the Middle East. During an outbreak in the "meningitis belt" of Africa, from Senegal to western Ethiopia infection rates can be as high as 1000 per 100,000 population. In 2010, 24 African nations launched a large-scale vaccination program to vaccinate all those aged between 1 and 29 years against the predominant (80-85% of cases) circulating meningococcal serotype, A. Since then, the incidence of serotype A infections has been virtually eliminated. Serotypes C and W are now considered the predominant strains in the region.

Nigeria has recently announced (2024) that it will be the first country to implement a meningococcal vaccination program with the newly developed 5-strain vaccine (Men5CV). This vaccine will provide protection against the 5 most common circulating strains of meningococcal in the world, serotypes ACWY and B. This may be the first step for sub-Saharan Africa towards dramatically reducing meningococcal outbreaks and mortality.

In high-income countries such as Australia and New Zealand, invasive meningococcal disease is rare; around 0.5 to 10 cases per 100, 000 population. Localised outbreaks tend to be caused by serotypes B and C; serotype B is more likely to cause invasive meningococcal disease. It is more commonly a disease of small children and young adults, but any age can be affected.

Invasive meningococcal (symptoms including headache, neck stiffness, fever) is a medical emergency. Early intervention and appropriate use of antibiotics have been shown to dramatically reduce mortality rates and permanent complications.

Meningitis is a notifiable disease in Australia.

One hundred and 45 cases have been reported for the year ending April 28th, 2024. This is in line with the 5-year rolling average.

Meningitis ACYW vaccination is available (free) under the NIP to:

• infants aged 12 months
• adolescents 15-19 years (usually in school-based programs or via a GP)
• individuals with no spleen or poorly functioning spleens
• individuals with a complement deficiency syndrome
• individuals taking the medication, eculizumab

Meningitis B vaccination is available (free) under the NIP to:

• Aboriginal children up to 2 years of age
• individuals with no spleens or poorly functioning spleens
• individuals with a complement deficiency syndrome
• individuals taking the medication, eculizumab

The vaccine is also available under a state-based vaccination program in South Australia, where it is available (free) to infants at 2, 4, and 12 months.

Overall, travellers have a low risk of contracting meningococcal disease.

Long-term travellers and expatriates living endemic areas and in close contact with unvaccinated local populations are at greatest risk.

Vaccination should be considered in those travellers who may have prolonged contact with locals when visiting epidemic areas of Africa during the high-risk season (December to June). These include Uganda, Nigeria, Kenya, Cameroon, Democratic Republic of the Congo, Rwanda, Burundi). Vaccination is usually recommended by international agencies and NGO workers in high-risk areas. Healthcare workers should be vaccinated irrespective of the time of year.

Proof of vaccination (issued at least 10 days before arrival) is required by the Saudi Arabian government from those visiting Mecca during the annual Haj and Umrah pilgrimages. The vaccine administration date must be within the last 5 years.

Travellers with anatomical or functional asplenia are deemed to be at higher risk of invasive meningococcal disease and vaccination is recommended.