The Epidemiology of Meningococcal Disease in New Zealand in 2012

Sunday 16th December 2018


Key findings of meningococcal disease surveillance in 2012

Eighty-five cases of meningococcal disease were notified. This equates to a notification rate of 1.9 per 100 000 population, the lowest rate of meningococcal disease in New Zealand for two decades. The number of confirmed cases was 74, giving a confirmation rate of 87.1%.

Canterbury District Health Board had the highest number of cases (10), followed by Waitemata (9) and Capital & Coast (9) District Health Boards (DHBs). The highest rates of disease were in Taranaki (5.4 per 100 000 population, 6 cases) and Lakes (4.8 per 100 000 population, 5 cases) DHBs.

The highest age-specific rates of meningococcal disease continued to occur in children younger than five years: 19.8 per 100 000 population for those aged less than one year and 5.6 per 100 000 population for those aged 1–4 years. As in previous years a secondary peak in the notification rate was observed for the 15–19 years age group (4.8 per 100 000 population). The 2012 rates of disease for the less than one year and 1–4 year age groups were around half the previous year’s rates (38.5 per 100 000 and 12.7 per 100 000, respectively, in 2011).

Although age-standardised rates decreased for all ethnic groups between 2008 and 2012, Māori and Pacific Peoples continued to experience higher rates of disease than the European or Other ethnic group in 2012. The highest disease rate was in the Māori ethnic group (3.3 per 100 000 population, 29 cases), followed by Pacific Peoples (3.0 per 100 000 population, 10 cases) and European or Other (1.5 per 100 000 population, 42 cases) ethnic groups.

The strain type was determined for 68 (91.9%) of the 74 confirmed meningococcal disease cases. Over 60% of cases were group B strains and approximately 33% were group C strains, with 22.1% due to group B:P1.7-2,4 and 26.5% due to group C:P1.5-1,10-8.

Hospitalisation status was recorded for all notified cases, and 82 (96.5%) were hospitalised. Of the three cases that were not hospitalised, two died.

Six fatalities occurred, giving a case-fatality rate of 7.1%. All fatalities in 2012 were confirmed cases. Four fatalities were due to group C strains, including three with group C:P1.5-1,10-8 strain. Two were group B strains, one with group B:P1.7-2,4 strain.

The case-fatality rate for group C disease was 17.4% and for group B disease was 4.7%.

The antimicrobial susceptibility of 50 viable meningococcal isolates, received by ESR from cases of invasive disease in 2012, was tested. All isolates were susceptible to ceftriaxone, rifampicin and ciprofloxacin. More than 30% (16/50) had reduced susceptibility to penicillin, with minimum inhibitory concentrations (MICs) of 0.12–0.5 mg/L.

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The Epidemiology of Meningococcal Disease in New Zealand in 2012

 

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The Epidemiology of Meningococcal Disease in New Zealand in 2012

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