Meningococcal disease is caused by a bacterium called Neisseria meningitidis (also known as meningococcal bacteria). These bacteria are divided into 13 strains or ‘serogroups’ designated by letters of the alphabet such as A, B, C, W and Y.
The predominant strain changes over time. Disease due to strain C has decreased since the introduction of meningococcal C vaccine to the National Immunisation Program in 2003, with strain W currently the most common strain causing disease in Victoria. Different strains of bacteria have been found to cause meningococcal disease in different countries.
Some people have the bacteria living naturally in their nose and throat. In a small number of people, a dangerous strain of the bacteria can move through the lining of the throat, causing what is known as invasive meningococcal disease. This can take the form of a blood infection (septicaemia) or infection of the membranes covering the brain and spinal cord (meningitis). The infection can develop quickly and can cause serious illness or death. Early diagnosis and treatment with antibiotics are vital.
The meningococcal C vaccine provides good protection against strain C serogroups. The number of cases of C serogroups has decreased in Australia following the introduction of this vaccine. A meningococcal B strain vaccine that protects against about 76 per cent of B strain meningococcal serogroups is available to purchase on prescription.
Children aged less than five years, particularly infants aged less than one year, have the highest incidence of invasive meningococcal disease caused by meningococcal B serogroups. A lower, secondary peak in incidence is seen in late adolescence and early adulthood. People with a poor functioning spleen or who have had their spleen removed or who have a complement disorder should also have the meningococcal B vaccine.
In recent years the prevalence of the meningococcal W strain – one of the main meningococcal strains – has increased significantly across Australia, with Victoria experiencing 48 cases in 2016, compared to 17 cases in 2015, four in 2014 and just one in 2013.
A four in one combined vaccine against serogroups A, C, W and Y, and a vaccine against serogroups B are available and recommended for people to purchase who are at high risk of these bacterial strains.See vaccine recommendations for high risk groups.
These vaccines can also be purchased by people who wish to protect themselves or their family from meningococcal.
Overview of meningococcal disease
Meningococcal bacteria live naturally in the back of the nose and throat in about 10 per cent of the population without causing illness. In a small number of people, a particular strain of the bacteria gets through the lining of the throat, enters the bloodstream and causes invasive meningococcal disease.
The infection can develop very quickly. If infection is diagnosed early enough and the right antibiotics are given quickly, most people make a complete recovery. Even with antibiotic treatment, invasive meningococcal disease causes death in about five to 10 per cent of cases.
Most cases occur suddenly and are unrelated to any other cases. Outbreaks where more than one person is affected are rare. Although everyone is a carrier at some time, carriers are most common among young adults, especially men and smokers.
Causes of meningococcal disease
Meningococcal bacteria are difficult to spread. They are only passed from person to person by close, prolonged household and intimate contact with infected secretions from the back of the nose and throat. Some research shows that low levels of salivary contact are unlikely to transmit meningococcal bacteria. In fact, saliva has been shown to slow the growth of the bacteria.
Meningococcal bacteria are only found in humans and cannot live for more than a few seconds outside the body. You cannot catch meningococcal disease from the environment or animals. The bacteria cannot be picked up from water supplies, swimming pools, buildings or factories.
Meningococcal disease can occur all year round, but it is more common during winter and early spring.
High-risk groups for meningococcal disease
Although meningococcal disease is uncommon, it is a very serious disease that can occur in all age groups. In Victoria, the highest risk groups are children under five years of age and young adults aged 15 to 24 years. Since vaccination through the National Immunisation Program began in 2003, very few cases of meningococcal disease caused by serogroup C bacteria are seen in children under five years.
Vaccine recommendations for high risk groups
Speak to your doctor about which vaccine you should have (and how long protection will last) if you are in one of these high-risk groups, including:
- travellers to countries where epidemics of meningococcal disease occur
- infants and young children, particularly those aged less than two years
- adolescents aged 15 to 19 years
- people who have close household contact with those who have meningococcal disease and who have not been immunised
- people who are travelling to places, such as Africa, that have epidemics caused by serogroups A, C, W and Y
- pilgrims to the annual Hajj in Saudi Arabia -- Saudi Arabian authorities require a valid certificate of vaccination to enter the country
- people who work in a laboratory and who handle the meningococcal bacteria
- children aged from six weeks and over, and adults who have high-risk conditions, such as a poor functioning or no spleen, a complement component disorder, HIV, current or future treatment with eculizumab or a haematopoietic stem cell transplant.
Symptoms of meningococcal disease
Meningococcal bacteria can develop into invasive meningococcal disease and that causes a range of symptoms. If you (or your child) have any of these symptoms below, seek medical attention as soon as possible.
Symptoms in babies and young children
Symptoms of invasive meningococcal disease in infants and young children can include:
- refusing to feed
- irritability, fretfulness
- grunting or moaning
- extreme tiredness or floppiness
- dislike of being handled
- nausea or vomiting
- turning away from light (photophobia)
- convulsions (fits) or twitching
- rash of red or purple pinprick spots or larger bruises.
Symptoms in older children and adults
Symptoms of invasive meningococcal disease in older children and adults can include:
- loss of appetite
- neck stiffness
- discomfort when looking at bright lights (photophobia)
- nausea and/or vomiting
- aching or sore muscles
- painful or swollen joints
- difficulty walking
- general malaise
- moaning, unintelligible speech
- rash of red or purple pinprick spots or larger bruises.
Complications of meningococcal disease
People with meningococcal disease could develop other conditions including:
- meningitis – an infection of the membrane covering the brain (signs include fever, stiff neck, drowsiness, irritability and refusal of food)
- septicaemia – an infection of the blood
- pneumonia – lung inflammation
- arthritis – joint infection
- permanent brain damage
- death (five to10 per cent).
Complications such as meningitis and septicaemia are medical emergencies. If you think a person has symptoms that suggest meningitis or septicaemia as described above, contact your doctor immediately, call triple zero (000) for an ambulance or go to the nearest hospital emergency department.
About a quarter of the people who recover from meningococcal disease experience some after-effects of the infection. Most of these problems get better with time. Some of the more common after-effects include:
- skin scarring
- limb deformity
- deafness in one or both ears
- tinnitus (ringing in the ears)
- blurring and double vision
- aches and stiffness in the joints
- learning difficulties.
When to seek medical help for meningococcal disease
If somebody close to you has some of these signs and symptoms, and seems sicker than you would expect with a normal infection, seek medical help immediately. In the very early stages, meningococcal disease can appear to be like other, less serious illnesses. Your doctor may not immediately recognise this illness.
You are the expert in your family’s health. Do not hesitate to seek immediate medical help:
- if you are worried that the person is sicker than you would expect with a normal infection
- if the person seems to be getting worse, suddenly develops a rash or becomes drowsy
- even if it has only been an hour or two since you last sought help, you can always call NURSE-ON-CALL, triple zero (000) for an ambulance or go to an emergency department of a hospital.
Young adults and children should not be left alone if they suddenly develop a fever, as they may become seriously ill very quickly.
Diagnosis of meningococcal disease
Early diagnosis of invasive meningococcal disease is extremely important. Your doctor will take a medical history. If meningococcal disease is suspected, samples of blood and the fluid around the spinal cord (cerebrospinal fluid) are taken.
The samples are sent to a laboratory to be tested for the presence of meningococcal bacteria. Growing the bacteria confirms the diagnosis and will help to determine which type of bacteria is causing the infection.
Treatment of meningococcal disease
If meningococcal disease is suspected, an antibiotic (usually penicillin) is given immediately by injection. People with meningococcal disease are almost always admitted to hospital and may require admission to an intensive care unit.
The sooner people receive treatment, the less damage the disease will cause. It is important to remember that this is an unpredictable infection that can progress very rapidly, despite the best treatment.
Treatment of close contacts of people with meningococcal disease
Most people, such as school and work friends who have had contact with an affected person, do not need antibiotics.
Very close contacts of an infected person are offered a short course of ‘clearance’ antibiotics in accordance with Australian guidelines. These people are usually identified and contacted by the Department of Health and Human Services or the treating doctor. These antibiotics are effective at killing meningococcal bacteria in the throat. They are not a treatment for meningococcal disease, nor do they necessarily prevent anyone from developing the disease.
Very close contacts may include:
- members of the same household
- a girlfriend or boyfriend
- anyone who has stayed overnight in the same house as the person in the seven days before they became unwell.
- children in a childcare facility who have spent at least four hours or more in the same room as the affected person in the seven days before the person became unwell.
Immunisation against meningococcal disease
Immunisation against meningococcal bacteria is the best protection against meningococcal disease.
It is important to know that even if you have had meningococcal disease, you may not develop lifelong immunity and are still advised to be immunised against further recurrence of this life-threatening disease.
Meningococcal C vaccination
Immunisation against meningococcal serogroup C disease is available for free in Victoria as part of the National Immunisation Program schedule for:
- children at 12 months – immunisation against meningococcal serogroup C is given in combination with the booster dose of vaccine against Haemophilus influenza type b (Hib)
- children from 13 months to under 20 years of age, to catch up.
Meningococcal B vaccination
Immunisation against meningococcal serogroup B disease is available on private prescription, but is not available free under the National Immunisation Program schedule. This vaccine is recommended for high risk groups as identified above.
Meningococcal serogroup B vaccine commonly causes fever in children younger than two years of age and skin reactions at the injection site. Paracetamol is recommended 30 minutes before or as soon as practicable after meningococcal B vaccine for children younger than two years of age. Two further doses of paracetamol are recommended six hours apart, regardless of whether fever is present.
Meningococcal ACWY vaccination
A free meningococcal ACWY vaccination program for gay and bisexual men (GBM) and men who have sex with men (MSM) living in Victoria, commenced on 11 December 2017 and ends on 31 December 2018.
A free meningococcal ACWY vaccination program will commence in Victoria on 1 January 2018 for secondary school students in Year 10 (or age equivalent not attending school) and ends 31 December 2018.
Immunisation against meningococcal serogroups A, C, W and Y is available in a four-in-one combined vaccine and can be purchased by anyone wishing to protect themselves or their family. This vaccine is recommended for high risk groups as identiied above,
Pregnancy and meningococcal disease immunisation
Meningococcal vaccines are not usually recommended for women who are pregnant, but they might be given if your doctor thinks your situation puts you at risk of the disease.
Where to get help