Invasive pneumococcal disease and serotype emergence in the Auckland region during the vaccine era 2009–16

Abstract

INTRODUCTIONThere is a deficit of knowledge in New Zealand as the epidemiology of invasive pneumococcal disease varies significantly between countries. AIMTime trends and sociodemographic characteristics of cases of invasive pneumococcal disease (IPD) in the Auckland region are reviewed after the introduction of a conjugate vaccination, to provide evidence for future vaccine policy and to ensure Auckland region analysis is representative of national trends for subsequent IPD analysis. METHODSData on all cases of IPD occurring in Waitemata, Auckland and Counties Manukau District Health Boards between 2009 and 2016 were extracted from EpiSurv. Denominator data were drawn from mid-year estimates supplied by Statistics New Zealand. Descriptive epidemiology and time-series regression was performed to analyse trends. RESULTSRates of IPD have fallen in the Auckland region over the past 8 years by 32%. While absolute rates in the elderly have reduced by 12%, they have the highest disease burden at 32/100,000. The ethnic disparity continues with Pacific people (33/100,000) and Māori (14/100,000) over represented compared to European (10/100,000). In the elderly, the 19A serotype has increased from an incidence of 0 in 2008 to 8.2/100,000. DISCUSSIONLarge ethnic and age-related disparities are observed in the Auckland region, consistent with the rest of the country, since the start of the pneumococcal vaccination era. Extending immunisation to the elderly may help close these gaps. As with other countries, there is 19A serotype replacement occurring following conjugate vaccine introduction.

From the Editor: Aspirations, innovations and reality

“…The other clinically-oriented papers in this issue relate to pneumococcal disease, 8 mental health, 9 exostoses in surfers, 10 and dermoscope-guided surgical procedures in general practice. 11 Descriptive epidemiology such as the approach presented in the article by Eichler et al 8 is sometimes regarded as rather pedestrian by our public health colleagues but for people working in primary healthcare and delivering vaccines it is both useful and reassuring to have access to this sort of analysis. This paper documents changes in vaccines to cover increasing numbers of pneumococcal serotypes and demonstrates how vaccinating preschool children has produced indirect herd immunity for the elderly, reducing the incidence of pneumococcal disease in both population groups.…”