Meningococcal disease

  • Overview
  • In Depth
  • Vaccines
  • Video

Meningococcal disease is caused by the bacterium Neisseria meningitidis. At least 13 groups have been identified and of these groups A, B, C, Y and W-135 are the most likely to cause disease in humans.

Patterns of infection differ throughout the world. In New Zealand groups B and C are most likely to cause disease.

Humans are the only host of these bacteria.

A brief history

Although the first known epidemic of meningococcal disease was reported in 1661 the actual bacterium causing the disease was not identified until 1887 and the first publication about meningococcal meningitis not until 1905.

Although group A is the most common cause of meningococcal disease worldwide in New Zealand groups B and C are more likely to cause disease.

Vaccines that protect against meningococcal disease have been around since the 1970s but none protect against all groups that cause disease. Typically they protect against disease by groups A, C, W135 and Y because the group B meningococcus is the most effective at evading the human immune response to eliminate it.

New Zealand, Norway and Cuba have used specially manufactured vaccines against a single specific strain of meningococcal group B to slow and eventually stop epidemic levels of disease.

There are no vaccines currently available in New Zealand that protect against meningococcal group B. However, new meningococcal B vaccines have been licensed overseas.

NZ Situation

In New Zealand most cases of meningococcal disease are caused by groups B and C. Disease caused by groups A, Y and W135 is infrequent.

The rate of meningococcal disease in 2011 was similar to the disease rates in the previous four years. Children less than five years who are Māori or Pacific people are over-represented in those who get meningococcal disease in New Zealand.

There have been isolated outbreaks of meningococcal groups A and C in New Zealand. The last group A outbreak was in 1985/86 in Auckland.

A New Zealand only strain of meningococcal group B bacterium caused an epidemic between 1991-2007. The epidemic mainly affected infants less than one year of age who were Māori or Pacific peoples and children aged one to four years who were of other ethnicity.

The most recent group C outbreak was in Northland during 2011.

Symptoms

Initial symptoms are difficult to distinguish between other viral, e.g. influenza, or bacterial infections. They usually start and progress quickly, often within 24 hours. However, infants tend to have a more gradual onset than adults.

Infants may:
Infants may have a fever, cry, appear unsettled, feed poorly, vomit, be sleepy or hard to wake, dislike bright light or have a rash or spots. They may have a bulging fontanelle.

Older children and adults may:
Have a fever, malaise, nausea, vomiting, muscle aches and pains, drowsiness, headache, dislike of bright light, neck stiffness or have a rash or spots.

Almost 80% of cases will develop a rash that does not blanch (become pale/go white) when pressed on. This type of rash is often a late sign of infection.

How do you get it?

Meningococcal bacteria are commonly carried in the nose and throat, and do not usually cause disease. The bacteria can be transferred from person to person through contact with saliva, e.g. intimate kissing. Saliva on shared drink bottles or pacifiers (dummies) may also have a limited role in passing the bacteria from one person to another. The bacteria may also be shared through droplets of saliva in the air from people coughing, sneezing or laughing.

What are the risks?

If meningococcal bacteria pass into the blood, disease usually progresses very quickly. A person with meningococcal disease may develop:

  • Meningitis (inflammation of the membranes around the brain).
  • Septicaemia (blood infection).
  • Pneumonia (lung inflammation).
  • One to two people out of every 10 who survive meningococcal disease have long term complications, e.g. extensive skin scarring, limb amputation, hearing loss, seizures or brain injury.
  • Even when the disease is identified and treated early, about one person out of every 10 will die.
Who is the most at risk?

Infants, children less than five years of age and adolescents have an increased risk of meningococcal disease. Infants less than one year of age and children less than five years who are Māori or Pacific Peoples have the highest risk.

Being exposed to tobacco smoke, living in a crowded household or having another respiratory infection, e.g. influenza, can increase a person’s chances of carrying the bacteria.

Some groups are also at increased risk of infection: household and other close contacts of someone with the disease, e.g. those who have been intimate or shared food and beverages, infants and children attending day care or an early childhood education centre, and adolescents and young people at boarding school or living in hostels.

Some people with medical conditions that affect their immune system have an increased risk of infection, e.g. their spleen has been removed or doesn’t work properly, and those who are immune compromised from a disease or treatment of a disease.

It is not clear why some people are vulnerable to the bacteria passing into their blood leading to disease.

Treating the symptoms

Prompt diagnosis and early administration of injected antibiotic to patients suspected of having meningococcal infection and arranging for prompt admission to the hospital may help decrease mortality and morbidity.

Antibiotic treatment for 5–7 days is adequate therapy for most meningococcal illnesses.

Preventing the disease from spreading

The risk of infection for household contacts of a person with the disease is highest during the first seven days and may persist for many weeks. Preventive antibiotics should be administered to close contacts as soon as possible, preferably within 24 hours of identification of the person with meningococcal disease.

During an outbreak a meningococcal immunisation programme may be commenced for those in the highest risk groups if a vaccine is available. High numbers of people immunised with a type of meningococcal vaccine called a conjugate vaccine can protect individuals and also reduce the spread of disease. This is because the conjugate vaccine reduces the number of people carrying N. meningitidis contributing to ‘herd immunity’ whilst protecting the individual from invasive disease.

Risk of disease vs. vaccine side effects
Meningococcal disease Effects of disease Side effects of vaccine

Meningococcal disease is caused by the bacterium Neisseria meningitidis and can cause meningitis, septicaemia, long term complications or death.

  • Meningitis (inflammation of the membranes around the brain).
  • Septicaemia (blood infection).
  • Inflammation of the membranes around the brain (meningitis).
  • Blood infection (septicaemia).
  • Pneumonia.
  • One to two people out of every 10 who survive have long term complications, e.g. extensive skin scarring, limb amputation, hearing loss, seizures or brain injury.
  • Even when the disease is identified and treated quickly, about one to two people out of every 10 will die.
Common side effects
  • Mild pain, redness and swelling around injection site.
  • Mild fever.
  • Decreased appetite, nausea, vomiting or diarrhoea.
  • Irritability.
  • Headache.
  • Fatigue, malaise, drowsiness.
Uncommon side effects
Rare/very rare side effects
  • Urticaria.
  • Anaphylaxis (severe allergic reaction).

Meningococcal disease is caused by the bacterium Neisseria meningitidis. At least 13 groups have been identified and of these groups A, B, C, Y and W-135 are the most likely to cause disease in humans.

Patterns of infection differ throughout the world. In New Zealand groups B and C are most likely to cause disease.

Humans are the only host of these bacteria.

Causative organism

Neisseria meningitides is a gram-negative encapsulated, aerobic diplococcus bacterium. At least 13 serogroups have been identified and of these groups A, B, C, W135 and Y usually cause disease in humans. Different countries experience different rates of infection with each of the serogroups. In New Zealand groups B and C are most likely to cause disease.

Meningococci are further classified into types and subtypes, determined by the immunological reactivity to the PorA and PorB outer membrane proteins (OMPs) and the VR epitopes within the PorA and PorB proteins. For example the New Zealand specific meningococcal B strain that caused an epidemic between 1991-2007 was classified as (B:4:P1.7b,4).

N. meningitidis has a rapid ‘doubling time’ i.e. rapidly reproduces itself, and releases toxins, harmful porin proteins and DNA. These factors contribute to the severity of disease and rapid progression to cutaneous haemorrhage and skin necrosis, disseminated intravascular coagulation and shock.

Humans are the only host of these bacteria. The bacteria commonly colonise the nasopharynx and in most people carriage leads to immunity. However, in some people the bacteria invade the mucous membrane of the nasopharynx and cause non-invasive or invasive disease.

Clinical signs, symptoms and complications

he initial symptoms are difficult to distinguish from other infectious illnesses, e.g. influenza. Symptoms usually start and progress quickly, often within 24 hours. However, infants tend to have a more gradual onset than adults.

Infants

May have a fever, cry, appear unsettled, feed poorly, vomit, be sleepy or hard to wake, dislike bright light or have a rash or spots. They may have a bulging fontanelle.

Older children and adults

May have a fever, malaise, nausea, vomiting, muscle aches and pains, drowsiness, headache, dislike of bright light, neck stiffness or have a rash or spots.

Rash

Almost 80% of cases will develop a rash. The rash may begin as a blanching macula or maculopapular rash and progress to a haemorrhagic purpuric or petechial rash that does not blanch (become pale/go white) when pressed on.

Haemorrhagic rash is often a late sign of infection.

Method of transmission
  • Meningococcal bacteria are commonly carried in the nose and throat, and do not usually cause disease. The bacteria can be transferred from person to person through contact with saliva, e.g. intimate kissing.
  • The bacteria may also be shared through droplets of saliva in the air from people coughing, sneezing or laughing.
  • Saliva on shared drink bottles or pacifiers (dummies) may also have a limited role in passing the bacteria from one person to another.

 

Public health significance

Meningococcal disease is notifiable on suspicion of disease.

  • Infants, children less than five years of age and adolescents have an increased risk of meningococcal disease. Infants less than one year of age and children less than five years who are Māori or Pacific Peoples have the highest risk.
  • Being exposed to tobacco smoke, living in a crowded household or having another respiratory infection, e.g. influenza, can increase a person’s chances of carrying the bacteria.
  • Some groups are also at increased risk of infection: household and other close contacts of someone with the disease, e.g. those who have been intimate or shared food and beverages, infants and children attending day care or an early childhood education centre, and adolescents and young people at boarding school or living in hostels.
  • Some people with medical conditions that affect their immune system have an increased risk of infection, e.g. their spleen has been removed or doesn’t work properly, and those who are immune compromised from a disease or treatment of a disease.
  • It is not clear why some people are vulnerable to the bacteria passing into their blood leading to disease.
  • Health professionals in close contact with oropharyngeal secretions of patients with meningococcal disease, e.g. those performing mouth-to-mouth resuscitation or managing an endotracheal tube (placement and/or suctioning) prior to and during the first 24 hours of antibiotic treatment of the index case and microbiology laboratory workers are considered to be at increased risk of meningococcal disease.
Prevention

The risk of infection for household contacts of a person with the disease is highest during the first seven days and may persist for many weeks.

Preventive antibiotics should be administered to close contacts as soon as possible, preferably within 24 hours of identification of the person with meningococcal disease but can be commenced up to 14 days after the contact.

  • The recommended antibiotics for close contacts of the index case are rifampicin, ceftriaxone and ciprofloxacin. These antibiotics have been shown to eradicate nasopharyngeal N. meningitidis colonisation.
  • Antibiotic prophylaxis is not routinely recommended for health professionals.

During an outbreak a meningococcal immunisation programme may be commenced for those in the highest risk groups if a vaccine is available. High numbers of people immunised with a meningococcal conjugate vaccine can protect individuals and also reduce the spread of disease. This is because the conjugate vaccine reduces the number of people carrying N. meningitidis contributing to ‘herd immunity’ whilst protecting the individual from invasive disease.

Funded vaccines for special groups 

NeisVac-C® is the recommended and funded meningococcal vaccine for children under 2 years of age, and Menactra® is recommended and funded for children from 2 years of age, adolescents, and adults with functional asplenia or who have an inherited or acquired complement deficiency, or who are pre/post splenectomy; pre- or post-solid organ transplantation; post-haematopoeitic stem cell transplantation; immunosuppressed for longer than 28 days; HIV-positive; or a close contact of a meningococcal disease case.

Treatment

A Cochrane review in 2008 found that the evidence from case control studies suggested that early diagnosis, early admission to hospital (within three hours) and early instigation of supportive measures, including fluid therapy, are as important as the early commencement of antibiotics.

Prompt diagnosis and early administration of injected antibiotic to patients suspected of having meningococcal infection and arranging for prompt admission to the hospital may help decrease mortality and morbidity.

  • Penicillin or a broader spectrum antibiotic e.g. cefotaxime or ceftriaxone should be administered intravenously or intramuscularly on suspicion of meningococcal disease before the person is transferred to hospital.
    • General practitioners need not be concerned that empiric penicillin will obscure the diagnosis for hospital clinicians.
  • Antibiotic treatment for 5–7 days is adequate therapy for most systemic meningococcal illnesses.

NeisVac-C®

Meningococcal C conjugate vaccine

NeisVac-C® is a meningococcal C conjugate vaccine used to protect against Neisseria meningitidis group C only.

The conjugate and polysaccharide vaccines work differently to generate protection against the bacteria. Protection from the conjugate vaccines lasts longer than that from the polysaccharide vaccines. The conjugate vaccines also generate long term memory cells allowing rapid boosting of immunity years later.

 

Menactra®

Meningococcal A,C,Y,W135 conjugate vaccine

Menactra® is a meningococcal A,C,Y,W-135 conjugate vaccine used to protect against four groups of Neisseria meningitidis, group A, group C, group Y and group W-135.

Menactra® is used as an alternative vaccine to the meningococcal C conjugate vaccine (Neisvac-C™), meningococcal A,C,Y,W-135 conjugate vaccine (Nimenrix®) and the meningococcal A,C,Y,W-135 polysaccharide vaccine (Mencevax® ACYW).

The conjugate and polysaccharide vaccines work differently to generate protection against the bacteria. Protection from the conjugate vaccines lasts longer than that from the polysaccharide vaccines. The conjugate vaccines also generate long term memory cells allowing rapid boosting of immunity years later.

Nimenrix®

Meningococcal A,C,Y,W135 conjugate vaccine

Nimenrix® is a meningococcal A,C,Y,W-135 conjugate vaccine used to protect against four groups of Neisseria meningitidis, group A, group C, group Y and group W-135.

Nimenrix® is used as an alternative vaccine to the meningococcal C conjugate vaccine (Neisvac-C™), meningococcal A,C,Y,W-135 conjugate vaccine (Menactra®) and the meningococcal A,C,Y,W-135 polysaccharide vaccine (Mencevax® ACYW).

The conjugate and polysaccharide vaccines work differently to generate protection against the bacteria. Protection from the conjugate vaccines lasts longer than that from the polysaccharide vaccines. The conjugate vaccines also generate long term memory cells allowing rapid boosting of immunity years later.

Mencevax® ACWY

Meningococcal A,C,Y,W135 polysaccharide vaccine

Supply of Mencevax® ACWY has been discontinued in New Zealand. Menactra® and Nimenrix® are alternative vaccine brands.

Listed below are the available videos for this disease