What is the issue?
Invasive Meningococcal Disease (IMD) is caused by the bacteria Neisseria meningitidis. Approximately 10 per cent of the population are asymptomatic carriers of meningococcal bacteria in the upper respiratory tract, however IMD can occur in a small number of people.
Six serogroups of meningococcal bacteria (A, B, C, W, X and Y) account for most cases of IMD. Serogroup C cases have declined significantly since 2003 when the meningococcal C vaccine was added to the National Immunisation Program. Until recently, serogroup B was the most common cause of IMD in Victoria, with meningococcal serogroups A, W and Y less common in Victoria, despite being more common overseas.
Since January 2014, the department has observed an increase in notifications of IMD due to serogroup W in Victoria. There have been 13 cases notified in 2016 to date, compared with 17 cases in 2015, four cases in 2014 and one case in 2013. Rates of disease have been highest in older adults aged over 50 years, adolescents and young adults aged 15-24 years, and infants and young children aged under 5 years. The identified strain is similar to those that have been circulating in the United Kingdom and South America since 2009.
Who is at risk?
Anyone is potentially susceptible to strains of meningococcal infection for which they have not been vaccinated. However those at greater risk of serogroup W disease include:
- Older adults aged over 55 years
- Adolescents and young adults
- Young children and infants aged less than 5 years.
- People with pre-existing medical conditions, occupational exposures or travel.
Symptoms / transmission
The most common presentation of meningococcal serogroup W disease in Victoria has been severe sepsis (bacteraemia). Classical meningitis symptoms have been less common. Atypical presentations have been a feature, including septic arthritis and epiglottitis in older age groups. Pneumonia has been documented in the international literature.
Prevention and treatment
Consider testing for IMD - Meningococcal serogroup W disease should be considered as a differential diagnosis of atypical infections in older patients. Testing should occur prior to administration of antibiotics where possible. Discuss with local infectious diseases or microbiology experts when considering testing options.
Notify the department immediately on 1300 651 160 (24 hours a day) of all suspected and confirmed cases of IMD.
The Australian Immunisation Handbook 10th Edition, online version provides current guidance on meningococcal immunisation recommendations.
- Meningococcal serogroup W - quadrivalent meningococcal vaccines (4vMenCV and 4vMenPV). Available on private script. Recommended for occupational exposures, travel and certain medical conditions. This can be also offered to those who wish to protect themselves or their family from the disease.
- Meningococcal C conjugate vaccine (MenCCV) - Available through the National Immunisation Program. Recommended for all children at 12 months of age.
- Meningococcal B vaccine (MenBV) - Available on private script. Recommended for infants and young children, adolescents, young adults living in close quarters, some laboratory personnel and individuals with certain medical conditions.
Clearance antibiotics for the general population is not necessary -Testing for meningococcal carriage in asymptomatic individuals and treatment with clearance antibiotics is not required for the general population, and can be harmful by removing protective strains of bacteria and leading to antibiotic resistance. Following notification of suspected cases, the department will identify who should receive clearance antibiotics (generally close household and/or intimate contacts).
Communicable Diseases Prevention and Control Unit, Department of Health and Human Services
Telephone: 1300 651 160