Stopping the spread (of Meningococcal W in Western Australia)
Invasive meningococcal disease (IMD) has been on the rise in Western Australia (WA), with nearly half of cases presenting as meningococcal serogroup W (MenW).
Since 2013, UWA experts in IMD and MenW have advocated to the WA government for the need to deliver vaccinations to the community.
What is IMD?
IMD is a rare but life threatening disease caused by Neisseria meningitidis, a bacterium that naturally and harmlessly resides in the back of the nose or throat of about 10-20% of the human population. It can be spread by coughing, sneezing or kissing, and if transmitted to someone sensitive to that strain, will invade their bloodstream, causing rapidly fatal sepsis and meningitis.
If antibiotics are prescribed early, patients can survive IMD. Delayed treatment increases the risk of amputation or death.
There are 12 known sub-types of IMD, however the five main serogroups observed in WA are A C W Y and B. All IMD cases in Australia are recorded under the Australian Meningococcal Surveillance Programme.
IMD research at UWA
Dr Charlene Kahler, one of Perth’s leading microbiologists is the Deputy Director of The Marshall Centre for Infectious Diseases Research and Training at UWA. She leads the Marshall Centre Neisseria Research Group (NRG).
Dr Kahler first predicted that MenW would rise in incidence in WA after a similar outbreak occurred in Europe in 2012. With the financial support of the Amanda Young Foundation, she instructed her team to monitor and study MenW. The isolates were collected by PathWest (the state reference pathology laboratory) through a collaboration with Dr David Speers and Dr Tony Keil.
The strains were genotyped and compared to international data which allowed them to track the outbreak. The Marshall Centre NRG also provide their results to the National Neisseria Network which is conducting a national sequencing program to monitor the outbreak across Australia. [Source: Australian Government Department of Health] Since 2016, both the number of IMD cases and MenW cases have rapidly increased across all states and territories in Australia. In the past two years, children under five made up one third of all cases of IMD in WA, with 70% attributable to the MenW strain. In 2017, incidence of MenW and MenY were the most ever recorded in WA.
|Total IMD cases in WA since 2013|
In 2017, Dr Kahler’s PhD student Shakeel Mowlaboccus published a series of papers examining the rise in IMD and the appearance of penicillin resistance in these strains. He has recently received a small research grant from The Australian Society for Antimicrobials to support his work.
“Cases started to rise and at the same time, the bacteria became resistant to penicillin. We can’t underestimate this disease.”
There were two main research goals:
Why the rapid increase in the number of IMD cases?
Asymptomatic carriage of Neisseria meningitidis is common in young adults (15-25 yrs old) as they are very social and transmission is highest in this group. When that carriage rate is very high, transmission into other age groups is more frequent. IMD is most frequent in children under the age of two, where the immune system is still immature and unable to prevent the bacteria from causing disease. This is why there is peak of IMD in both young adults and children.
The UWA Marshall Centre NRG is investigating the emergence of new variants of MenW that maybe more virulent than usual in young children.
Were the strains becoming resistant to antibiotics?
Penicillin is the first line of treatment for IMD in the public health clinics. Alarmingly, the Marshall Centre NRG identified MenW strains that are now resistant to penicillin.
Whilst sequencing the DNA genomes of WA MenW, some strains were sensitive to penicillin while others were not. An examination of the sequences has allowed them to identify the gene that is responsible for the resistance to penicillin in these strains.
Because of this research, diagnostic labs world-wide can now predict the resistance of MenW to penicillin based on the sequence of that one gene, to confirm that the penicillin treatment is still effective in patients. This diagnostic test will provide an early warning to clinicians to use alternative treatments in a timely fashion to ensure patients have the best care and outcomes.
The UWA Marshall Centre NRG is continuing to monitor MenW to detect antibiotic resistance and provide early alerts to diagnostic laboratories world-wide.
WA Vaccination program
In late 2016, WA experienced its first outbreak of IMD in 30 yrs. An unprecedented five cases of MenW in one week which resulted in two deaths occurred in the Goldfields region in WA.
The UWA Marshall Centre NRG confirmed that these cases were caused by genetically related MenW, a hall-mark of an outbreak. Of increased concern was that these MenW strains had an increased resistance to penicillin which raised concerns around emergency treatment options in hospital clinics.
Once antibiotics stop working, there is only one way to go, [preventative] vaccination.
Dr Charlene Kahler
The WA Department of Health introduced an emergency, targeted ACWY vaccination program across Kalgoorlie, Boulder, Coolgardie and Kambalda. 1500 immunisations were administered in the first three days of the program and this has reduced the burden of disease in these areas.
WA has led the nation in the provision of this vaccine (ACWY), taking preventative action at a local level rather than waiting for a national immunisation program to be developed.
WA Health Minister Hon. Roger Cook, May 2017
Despite the success of vaccination in this local region, IMD continued to spread across the rest of WA in 2017. In response to the rise in the number of MenW cases across Australia, WA, the Northern Territory, New South Wales, Queensland, Tasmania, Victoria and the Australian Capital Territory committed to state-based ACWY vaccination programs.
“The best way to get rid of it is not to treat it, but instead to eradicate it with the help of prevention, which is vaccination.
In 2018, the free vaccination program was expanded to include children under the age of five. A second catch up campaign will begin mid-year 2018 to vaccinate young adults in the 18-25 year old range across the state.
If we can stop meningococcal disease in Western Australia today and tomorrow then we’ve saved a lot of lives so I’d really urge everyone to take this opportunity to get vaccinated.
Dr Charlene Kahler
Whilst the vaccination programs provide protection against the serogroups A C W Y, they do not include MenB, which currently makes up one third of IMD cases in WA. The vaccine for MenB is called Bexsero®. This vaccine is not currently available on the National Immunisation Program (NIP) Schedule but can be purchased at your local surgery.
Dr Kahler is currently a consultant on the “B part of it” vaccination trail in South Australia examining the impact of immunising large community groups against this form of the disease with Bexsero®. The intention is that the data from this trial will assist efforts for Bexsero® vaccine to be made available nationally and for free on the NIP schedule.
The Amanda Young Foundation
Dr Kahler believes that the most important part of her work is to be an advocate for the community in promoting vaccination and providing up-to-date information to families who have experienced the disease. Working in the nexus between the Departments of Health, diagnostic pathology laboratories and cutting edge science has been really exciting. But the most important group are families who have experienced IMD and who are seeking to support any new initiatives to prevent this from happening to other community members.
I believe that my work can really make a difference to the community and I really appreciate how the Amanda Young Foundation has connected me to families who have experienced this disease. To know that I can make a difference to them is really important in motivating me
Dr Charlene Kahler
The Amanda Young Foundation (https://www.amandayoungfoundation.org.au/) has supported the Marshall Centre NRG for many years and is pivotal to motivating her group to do more. The Foundation was created by Barry and Lorraine Young when their only child Amanda died as a result of IMD. They have created a lively community who are involved in diverse activities to raise community awareness regarding IMD, support groups for survivors, and educational programs including support for young leaders and research activities.