Increase in Neisseria meningitidis serogroup W invasive disease in Canada: 2009–2016

Whole genome typing of the recently emerged Canadian serogroup W Neisseria meningitidis sequence type 11 clonal complex isolates associated with invasive meningococcal disease

“…Beginning in 2014, a significant shift in the genetic makeup of invasive MenW strains was noted, from ST-22 CC to ST-11 CC (Tsang et al, 2016). Concomitant to this genetic shift in the MenW strain was the increase in the proportion of IMD due to MenW (Tsang et al, 2017). The MenW ST-11 CC isolates have been shown to be unrelated to the contemporary MenC ST-11 CC isolates; therefore, they did not arise from the contemporary MenC strains by capsule switching.…”

“…Unlike the recent MenW ST-11 disease in the UK, which began in the older adults and spread to all age groups including adolescents and infants , the Canadian MenW ST-11 cases have mostly occurred in the adult age group, with 62% of the cases older than 41 years of age (Tsang et al, 2017). MenW ST-11 disease in university students has also been reported from France (Bassi et al, 2017).…”

“…A similar increase in MenW disease due to the same strain has been observed in Australia since 2013 and has also led to the introduction of a targeted vaccination program for 0-4 and 15-19-year-olds in a region of western Australia (Martin et al, 2016;Media Statement, 2016). In Canada, the increase in MenW disease due to the ST-11 CC was first noted in 2014, and by 2016, ST-11 MenW was responsible for 19% of all culture-confirmed IMD (Tsang et al, 2016;Tsang et al, 2017).…”

Atypical presentation of invasive meningococcal disease caused by serogroup W meningococci

“…Tsang et al [7] The percentage of IMD caused by MenW increased in Canada between 2012 and 2016, associated with a greater prevalence of strain ST-11…”

“…However, the prevalence of disease caused by MenW has been increasing in Europe, Africa, North America, South America, Asia and the Middle East [5,[11][12][13][14][15]. The percentage of MenW cases in Australia increased from 8% in 2013 to 39% in 2016 [16] and from 3% in 2012 to 19% in 2016 in Canada [7]. In France, the South American/UK strain was the most frequent MenW cc11 isolate found between 2010 and 2016.…”