Australian Meningococcal Surveillance Programme Annual Report, 2020.

Invasive meningococcal disease (IMD) is a notifiable disease in Australia, and both probable and laboratory-confirmed cases of IMD are reported to the National Notifiable Diseases Surveillance System (NNDSS). In 2020, there were 90 notifications of IMD, the lowest number documented since records began in the NNDSS in 1991. Of these, 97% (87/90) were laboratory-confirmed cases, with 70% (61/87) confirmed by bacterial culture and 30% (26/87) by nucleic acid amplification testing. The serogroup was determined for 85/87 laboratory-confirmed cases of IMD: serogroup B (MenB) accounted for 64% of infections (54/85); MenW for 19% (16/85); MenY for 16% (14/85); and MenC 1.2% (1/85). Fine typing was available on 60/85 (71%) of cases with serogroup determined; of the typed MenW, all were PorA antigen type P1.5,2 and sequence type 11, the hypervirulent strain reported in recent outbreaks in Australia and overseas. The primary peaks of IMD notifications in Australia in 2020 were observed in infants less than 1 year (16/87, 18%) and in adults aged 45-64 years (14/87, 16%). MenB infections predominated in those aged less than 5 years and 15-19 years; MenW and MenY infections predominated in those aged 45 years or more. All 61 IMD isolates were tested for antimicrobial susceptibility: none were penicillin resistant; however, 56/61 (92%) had decreased susceptibility to penicillin. All isolates were susceptible to ceftriaxone, ciprofloxacin and rifampicin.