5 million Swiss residents learn more aged ≥16 years were diagnosed with an IPD per year in mean (i.e. 14.2/100,000). It was possible to link approximately 90% of reported IPD cases with a corresponding pneumococcal isolate. Therefore, the completeness of this linkage was very high indicating a very high participation

of involved laboratories. During 2007–2010, incidence of IPD cases with known serotype has changed significantly in adults overall and in those ≥65 years in Switzerland. In addition, this study shows a changing serotype distribution of invasive S. pneumoniae isolates from 2003 to 2012. This has been described for the PCV7 versus non-PCV7 serotypes recently [9] but our study additionally shows the single serotype epidemiology

in Switzerland. The sharp increase of the non-PCV7 serotype 19A is remarkable and has also been observed in other countries [6], [23], [24] and [25]. However, it is not clear if the introduction of PCV7 is exclusively responsible for this observation [26] and [27]. A significant increase of other non-PCV7 serogroups/serotypes was detected which countered the drop of vaccine serotypes to a certain extent. Increasing numbers of isolates of serotypes 19A, 22F and 6C but not of serogroup 35 have also been described Ixazomib purchase in a study performed at the University Hospitals in Cleveland during 1999–2007 [28]. It is well known that IPD incidence rates increase with advancing age and with various comorbidities like immunosuppression, underlying respiratory diseases and chronic diseases [29]. Hence PPV23 vaccination was recommended for persons with increased risk for IPD (i.e. for those aged 65 years and older and those older than 2 years with known risk

factors for IPD) in Switzerland. However, despite the broad vaccine usage, the efficacy of PPV23 is generally described as being poor at least in preventing pneumonia [14]. These issues secondly cannot be confirmed or dismissed with our data but in those with a known PPV23 vaccination history, vaccinated patients had a lower proportion of IPD due to PPV23 serotypes, whereas the non-PPV23 serotype 6A was associated with previous PPV23 vaccination. This study identified individual serotypes which mainly caused IPD in elderly adults and/or in adults with comorbidities. Unfortunately, a few of those serotypes/serogroup are not covered, by PCV13 e.g. serogroups 15, 20 and 35. The latter showed an increasing trend from 2007 to 2010 and may therefore become more important in the future. Our study also illustrates that the serotype was related to the clinical manifestations which was also investigated in a previous study in the Netherlands [30]. A recent population based study from Denmark demonstrated that patients aged 5 years and older infected with serotypes/serogroups 31, 11A, 35F, 17F, 3, 16F, 19F, 15B or 10A more often died than those infected with serotype 1, from 1977 to 2007 [20].