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.
In 2017, numbers of serogroup W are decreasing compared to 2016 but remain historically high at 36. We are also seeing an increase in cases due to serogroup Y: in 2017 there were 17 cases of the Y strain; 9 in 2016 and 2015; and only one in 2014. There were six deaths overall from meningococcal disease in 2017 compared to three in 2016 and two in 2015.
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 the 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.
Adolescents aged 15 and 16 are the focus of this year’s 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 serogroups A, C, W and Y– quadrivalent meningococcal conjugate vaccines (4vMenCV). A free, time-limited school-based vaccination program is currently available for young people in Year 10 or those aged 15 or 16 years old. 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).
Clinical / industry information
Meningococcal ACWY vaccine for adolescents
Meningococcal disease - Disease information and advice
Meningococcal ACWY vaccine for adolescents - Better Health Channel
Meningococcal disease - Better Health
Meningococcal disease - Immunisation - Better Health
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Communicable Diseases Prevention and Control Unit, Department of Health & Human Services.
Telephone: 1300 651 160