Impact of pneumococcal vaccination in children on serotype distribution in adult community-acquired pneumonia using the serotype-specific multiplex urinary antigen detection assay

The aim of the study was to compare the distribution of the vaccine-serotypes covered by pneumococcal conjugate vaccines (PCV7 and PCV13) in adult patients with pneumococcal community-acquired pneumonia in Germany between the periods 2002-2006 and 2007-2011 using a novel serotype-specific multiplex urinary antigen detection assay (SSUA). Vaccination of children started with PCV7 in 2007, which was replaced by PCV13 in 2010. Following confirmation of the accuracy of SSUA in long-term stored urine samples from 112 patients with confirmed pneumonia and known pneumococcal serotype, urine samples of 391 CAPNETZ patients with documented pneumococcal pneumonia (i.e. positive BinaxNOW (R) Streptococcus pneumoniae urine antigen test) but unknown serotype were tested for the 13 vaccine-serotypes using SSUA. The proportion of PCV7-serotypes significantly decreased in adult patients with pneumonia from 30.6% (2002-6) to 13.3% (2007-11, p <0.001); in bacteremic pneumonia, PCV7-serotypes completely disappeared (3/14 versus 0/19, p = 0.058). Conversely, pneumococcal serotypes included by PCV13 remained stable during study period with a coverage of 61.5% (2002-06) and 59.7% (2007-11) in non-bacteremic pneumonia and 79% (for both periods) in bacteremic pneumonia, mainly due to an increase in pneumococcal serotypes 1, 3 and 7F during the second period. Thus, implementation of PCV7 in children in Germany in 2007 was associated with a significant decrease in vaccine-serotypes covered by PCV7 in adult patients with non-bacteremic pneumococcal pneumonia and with an elimination of PCV7 vaccine-serotypes in bacteremic pneumococcal pneumonia. PCV13 coverage remained high up to 2011, mainly due to an increase in serotypes 1, 3 and 7F.