Meningococcal disease is a highly uncommon illness, which according to the most recent available data, only affects 0.8 people per 1,000,000 in Australia (DoH 2022a).

Despite its rarity, meningococcal disease is a medical emergency with a 5 to 10% mortality rate and requires immediate diagnosis and treatment (Better Health Channel 2019).

What is Meningococcal Disease?

Meningococcal disease is a bacterial infection that typically presents as one or both of:

• Meningococcal meningitis (bacterial infection of the membranes of the brain and spinal cord)
• Meningococcal septicaemia (bacterial infection of the bloodstream).

(Queensland Government 2021)

In rare cases, it may lead to other localised infections including pneumonia, arthritis or conjunctivitis (AIH 2022).

Meningococcal disease is caused by a bacterium known as Neisseria meningitidis. There are 13 serogroups (strains) of the bacteria, each labelled by a particular letter of the alphabet, with strains B, C, W and Y being the most common in Australia (Better Health Channel 2019; DoH 2022a).

The most dominant serogroup in Australia has historically been B, which still comprises half of all reported cases. Serogroup C was once highly prevalent but was greatly reduced by the introduction of the Meningococcal C vaccine in 2003. The prevalence of serotypes W and Y has increased since 2013 (AIH 2022; DoH 2022a).

What Causes Meningococcal Disease?

Neisseria meningitidis bacteria naturally dwell in the nose and throat of about 10 to 20% of people at any given time without causing illness (DoH 2022b).

These carriers can spread the bacteria to other people via respiratory secretions such as coughing, sneezing or kissing. Despite this, it’s a very difficult bacteria to transmit because it can only survive outside of the human body for a few seconds, and in order to be acquired, requires prolonged contact with the mucous of an infected person (Healthy WA 2018; DoH 2022b).

Therefore, Neisseria meningitidis is most commonly spread from one person to another via:

• Living in the same household as an infected person
• Deep kissing with an infected person
• Attending childcare with an infected person for more than four continuous hours.

(Healthy WA 2018; Better Health Channel 2019)

While it is also possible to transmit the bacteria via sharing food and drinks, this is highly unlikely due to the bacteria’s short lifespan outside of the body. Furthermore, it cannot be transmitted via touching contaminated surfaces or objects because it dies too quickly (Healthy WA 2018).

In most cases, when someone acquires Neisseria meningitidis, their body produces sufficient antibodies to contain the infection and prevent it from spreading (Oakley 2014). This person will then become an asymptomatic carrier until the bacteria disappear on their own after a few weeks or months, often without the person ever knowing they were carrying it (Health.vic 2010).

However, in rare cases, the bacteria become invasive, spread and cause serious illness (DoH 2022a). This may occur if the person doesn’t have enough time to build up antibodies, or if they have a compromised immune system (Oakley 2014).

Those most likely to be carriers are adolescents and young adults, not due to their age itself but rather, due to social behaviours that increase the risk of transmission such as living in dormitories or military barracks, smoking, deep kissing and visiting bars (Burman et al. 2018).

In fact, it’s estimated that up to 23% of 19-year-olds are carrying the bacteria at any given time (Burman et al. 2018).

Risk Factors For Meningococcal Disease

While meningococcal disease can affect anyone, those who are at increased risk include:

• Children under two years of age
• Aboriginal and Torres Strait Islander peoples aged between 2 months and 19 years
• Adolescents and young adults aged between 15 and 19 years
• Adolescents and young adults aged between 15 and 24 years who are living together in close quarters (e.g. dormitories or military barracks)
• People with certain conditions that increase their risk of meningococcal disease (e.g. certain blood disorders or a compromised immune system)
• People living with others who have meningococcal disease
• Adolescents and young adults aged between 15 and 24 years who are exposed to tobacco smoke
• Travellers to countries where there are high rates of meningococcal disease
• Laboratory workers who handle Neisseria meningitidis bacteria.

(DoH 2022b; Healthdirect 2021)

Symptoms of Meningococcal Disease

Most symptoms of meningococcal disease are non-specific, especially in young children, and often have a sudden onset (NSW Health 2020). The incubation period is between 1 to 10 days, with symptoms usually appearing 3 to 4 days after contracting the bacteria (Health.vic 2015).

The characteristic rash, which presents as petechiae (small red or purple spots) or purpura (resembles reddish-purple bruising), is a common symptom occurring in 50 to 75% of meningococcal septicaemia cases (Oakley 2014). It’s caused by bleeding under the skin and is one of the clearest and most important signs that a person has meningococcal disease and requires urgent treatment (Carter 2019).

Other possible symptoms include:

(Better Health Channel 2019; RCHM 2018)

Diagnosing Meningococcal Disease

Any person displaying the symptoms of meningococcal disease must be diagnosed as soon as possible. Diagnosis involves taking blood and cerebrospinal fluid cultures (Better Health Channel 2019).

Treating Meningococcal Disease

Meningococcal disease can become fatal just hours after the onset of symptoms, with meningococcal septicaemia being one of the most rapidly-killing infectious diseases (Oakley 2014).

Antibiotic treatment (typically with penicillin and/or a third-generation cephalosporin) and supportive care in hospital must be commenced as urgently as possible to maximise the patient’s chance of survival. Due to the severity of the illness, antibiotics are usually administered even before the diagnosis has been confirmed (Oakley 2014; Healthy WA 2018; NSW Health 2020).

Complications of Meningococcal Disease

Despite the severity of the disease, many people with meningococcal disease make a full recovery. However, about 30 to 40% of cases result in long-term complications or disability. The W serogroup in particular has double the death rate of the other strains (AIH 2022; Healthy WA 2018).

Potential long-term complications of meningococcal disease include:

• Limb loss or deformation due to skin and tissue necrosis
• Joint aches or stiffness
• Scarring on the skin
• Tinnitus (ringing in ears)
• Deafness in one or both ears
• Kidney or liver failure
• Headaches
• Double or blurred vision
• Blindness
• Learning difficulties
• Neurological issues.

(DoH 2022b; Oakley 2014; AIH 2022)

Preventing Meningococcal Disease

The best way to prevent meningococcal disease is via vaccination. There are three types of meningococcal vaccine in Australia:

• Meningococcal B vaccine (protects against serogroup B)
• Meningococcal C vaccine (protects against serogroup C)
• Meningococcal ACWY vaccine (protects against serogroups A, C, W and Y).

(AIH 2022)

The Australian Immunisation Handbook recommends that any person over the age of 6 weeks who wishes to protect themselves against meningococcal disease receives both the MenB and MenACWY vaccines (AIH 2022).

References