Invasive Pneumococcal Disease Surveillance, 1 October to 31 December 2017

The number of notified cases of invasive pneumococcal disease (IPD) in the fourth quarter of 2017 was substantially less than the previous quarter, but slightly greater than the fourth quarter of 2016. Following the July 2011 replacement of the 7-valent pneumococcal conjugate vaccine (7vPCV) in the childhood immunisation program with the 13-valent pneumococcal conjugate vaccine (13vPCV), there was an initial relatively rapid decline in disease due to the additional 6 serotypes covered by the 13vPCV across all age groups, however in 2017 this decline is no longer evident. Additionally, over this period the number of cases due to the eleven serotypes additionally covered by the 23-valent pneumococcal polysaccharide vaccine (23vPPV) and also those serotypes not covered by any available vaccine has been increasing steadily across all age groups (Figure 1).