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.
Five serogroups of meningococcal bacteria (A, B, C, W 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, an increase in notifications of IMD due to serogroup W in Victoria has been observed. A total of 48 cases of serogroup W disease were notified in 2016 , compared with 17 cases in 2015, and four cases in 2014. 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 that which has 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 five years
- people with pre-existing medical conditions, occupational exposures or travel.
Older adolescents are the focus of the 4VMenCV program based on the recommendations of national immunisation experts as they are at increased risk of meningococcal disease and are also most likely to spread the disease to others. This is due to social behaviours that result in the disease being transmitted through close physical contact, such as frequent kissing, nightclub attendance, living in residential colleges, smoking and participation in other social activities that involve physical closeness.
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 conjugate vaccines (4vMenCV). A one year free school-based vaccination program for Meningococcal W for 15 to 19 year olds will commence in Term Two of the 2017 school year. The 4vMenCV is also available on private script and is recommended for occupational exposures, travel and certain medical conditions. The 4vMenCV can be also offered on private script 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).
Meningococcal disease - Disease information and advice
Meningococcal disease - Better Health
Meningococcal disease - Immunisation - Better Health
Communicable Diseases Prevention and Control Unit, Department of Health & Human Services.
Telephone: 1300 651 160