title: Rise in invasive serogroup W meningococcal disease in Australia 2013-2015.
abstract: Since 2013, there has been an increase in the number of notified cases of invasive meningococcal disease (IMD) due to serogroup W (MenW) in Australia. In response to this observed increase, the Communicable Diseases Network Australia convened a working group in 2015 to collate and analyse the epidemiology of MenW disease nationally. Enhanced surveillance data collected by jurisdictions were collated and analysed, and whole genome sequencing (WGS) of MenW isolates assessed the genomic relatedness of strains between 2012 and 2015. This report describes that epidemiology. Since 2013, the incidence and proportion of MenW has increased in Australia, rising from an average of 2% of all IMD cases annually (range 0% to 5%) between 1991 and 2012; to 8% (12/149) of cases in 2013, 10% (17/169) in 2014, and 19% (34/182) in 2015. Victoria has been the main affected state, with 50% (17/34) of national cases in 2015. MenW has affected older populations, with a median age between 2003 and 2015 being 44 years. During this period, case fatality was 10.7% (17/159), 2.3 times higher than for all IMD serogroups combined (4.7%, 173/3720). There were 7 deaths due to MenW in 2015 (CFR 21%). WGS has found the majority of Australian isolates cluster within a group of W:P1.5,2:F1-1:ST11 isolates from the United Kingdom and South America, regions where rapid spread and endemic transmission has occurred since 2009. The recent increase in incidence of MenW in Australia is evolving and is being closely monitored. Lessons learned from the international experience will be important in informing the public health response.
authors.affiliation: Epidemiologist, Assistant Director, Immunisation Branch, Office of Health Protection, Australian Government Department of Health, Canberra, Australian Capital Territory.
authors.forename: Nicolee V
authors.initials: NV
authors.lastname: Martin
authors.affiliation: Senior Medical Advisor, Department of Health and Human Services, Victoria.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Ong
authors.affiliation: Director, Microbiological Diagnostic Unit Public Health Laboratory, Medical Director, Doherty Applied Microbial Genomics, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Howden
authors.affiliation: Director, WHO Collaborating Centre for STD and Neisseria Reference Laboratory, Microbiology Department, South Eastern Area Laboratory Services, the Prince of Wales Hospital, Sydney, New South Wales.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Lahra
authors.affiliation: Senior Medical Officer, Communicable Diseases Branch, Prevention Division, Queensland Health.|UQ Child Health Research Centre, Faculty of Medicine and Biomedical Sciences, The University of Queensland, Queensland.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Lambert
authors.affiliation: Staff Specialist, Public Health Physician, National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, the Children's Hospital at Westmead, New South Wales.
authors.forename: Frank H
authors.initials: FH
authors.lastname: Beard
authors.affiliation: Medical Epidemiologist, Communicable Disease Control Directorate, Department of Health, Western Australia.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Dowse
authors.affiliation: Epidemiologist, Vaccine Preventable Diseases, Communicable Disease Branch, Health Protection NSW, Sydney New South Wales.
authors.forename: Nathan
authors.initials: N
authors.lastname: Saul
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D021821:Communicable Diseases, Emerging; D005260:Female; D016680:Genome, Bacterial; D005843:Geography; D049674:History, 21st Century; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000266:history / Q000382:microbiology*; D008875:Middle Aged; D009026:Mortality; D009345:Neisseria meningitidis / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D011159:Population Surveillance; D065288:Serogroup; D055815:Young Adult