Invasive Pneumococcal Disease in New Zealand, 2010

2. METHODS2.1 Surveillance methodsIn this report, data for 2009 and 2010 is based on IPD case notifications supplemented withserotype and antimicrobial susceptibility data from the laboratory-based surveillance ofinvasive S. pneumoniae isolates. Data for earlier years is from ESR‟s national laboratorybasedsurveillance of IPD.Since 17 October 2008, IPD has been notifiable to medical officers of health under the HealthAct 1956. Data on each case is entered at public health units (PHUs), via a secure web-basedportal, onto a computerised database (EpiSurv). The notification data is collated andanalysed on behalf of the Ministry of Health by ESR.For the national laboratory-based surveillance of IPD, diagnostic microbiology laboratories inNew Zealand are requested to refer all invasive isolates of S. pneumoniae [ie, isolates fromcerebrospinal fluid (CSF), blood or other normally sterile site] to ESR. In addition and lessfrequently, laboratories refer sterile site specimens to ESR to test for the presence ofpneumococcal DNA by PCR. At ESR all invasive isolates are serotyped and tested forsusceptibility to a range of antibiotics (see Section 2.2).The notification data in this report is based on the information recorded on EpiSurv as at17 February 2011. Any changes made to EpiSurv data by PHU staff after this date are notreflected in this report. Serotype and antimicrobial susceptibility data for invasive isolateswas matched with the relevant case notification.Except for disease rates by ethnicity and deprivation index, mid-year New Zealandpopulation estimates were used to calculate incidence rates. The 2006 census population datawas used to calculate ethnicity-specific IPD rates, and a prioritised approach was used withthe order of prioritisation as: Māori, Pacific Peoples, Other (other groups except European),and European. 8 Incidence rates are not presented for categories where there were