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Background: The objective of this study is to describe incidence and shifts of serotype and clonal distribution of invasive Streptococcus pneumoniae strains in four different age groups (<5 years, 5-17 years, 18-64 years and >65 years) during a period of intermediate PCV13 vaccination coverage (2011-2016) in Catalonia, Spain., Methods: We included all pneumococcal strains systematically sent to the Catalan support laboratory for molecular surveillance of invasive pneumococcal disease (IPD) located at Hospital Sant Joan de Deu, Barcelona. Two study periods were considered: 2011-13, early PCV13 vaccination period (EVP) and 2014-2016, late vaccination period (LVP)., Results: A total of 2142 strains were included in the study. Five years after intermediate introduction of PCV13 in our population, a significant decrease of overall incidence of IPD in children <5 years was observed (incidence rate ratio 0.5, 95% confidence interval 0.4-0.8). However, in seniors older than 65 years, a significant increase of overall incidence of IPD was observed (IRR 1.4, 95% CI 1.1-1.7). The contribution of PCV13 vaccine serotypes to IPD declined significantly in all age groups: from 59% to 38.1% in <5 years; 82.7% to 59% in 5-17 years, 47.8% to 34.1% in 18-64 years and 48.2% to 37% in >65 years. Results found when comparing both periods were consistent with IRRs observed year by year. In children <5 years, the three major serotypes detected were 1, 24F and 19A in EVP vs 24F, 14 and 10A in LVP. Among patients 5-17 years the first three serotypes were 1, 12F and 14 both in EVP and LVP. Among adults 18-64, the three major serotypes detected were 1, 12F and 8 vs 8, 12F and 3, respectively. Finally, in patients >65 years the most frequently isolated serotypes were 3, 19A and 7F vs 3, 14 and 12F, respectively. Regarding clonal complexes (CCs) expressing mainly PCV13 serotypes, significant decreases of the proportions of CC306, CC191 and CC320 were observed, while CC156 showed a significant increase. As for CCs expressing mostly non-PCV13 serotypes, significant increases in ST989, CC53 and CC404 were showed., Conclusions: Despite low vaccine coverage in our setting a significant decrease of incidence of IPD was observed in children younger than 5 years. The modest indirect protection against vaccine serotypes causing IPD in elderly indicate the need for the inclusion of more serotypes in future high-valent PCV and vaccinating old adults should be considered., Competing Interests: Competing Interests: Fernando Moraga-Llop reports participation in expert meetings and symposiums organized by Pfizer and GSK. Carmen Muñoz-Almagro reports travel grants, participation in expert meetings and a research grant from Pfizer laboratories outside the submitted work. Magda Campins reports participation as an investigator in clinical trials from GSK and in expert meetings and symposiums organized by Pfizer and GSK. Juan José García-García reports participation in expert meetings from Pfizer. All other authors declare no competing interests.

The susceptibilities of pneumococci recently collected (up to June 2009) in Spain (500 isolates nonsusceptible to oral penicillin and 150 susceptible isolates) from serotypes not included in the conjugate vaccine were determined. Most nonsusceptible isolates (53.6%) belonged to serotype 19A. Susceptibility rates in serotype 19A penicillin-intermediate (n = 201)/penicillin-resistant (n = 67) isolates were <33%/< or =6.0% (erythromycin and oral cephalosporins with defined breakpoints), 85.1%/11.9% (amoxicillin), and 96.0%/52.2% (cefotaxime), respectively. Low susceptibility to common oral beta-lactams was also found in serotypes 11A (95.5% susceptibility to cefotaxime and erythromycin) and 35B.

The 23-valent polysaccharide pneumococcal vaccine is currently recommended in elderly and high-risk adults. Its efficacy against invasive pneumococcal disease has been demonstrated, but its effectiveness in preventing pneumonia remains uncertain. This study assessed the clinical effectiveness of vaccination against pneumonia among middle-aged and older adults. We conducted a population-based case-control study including 304 case patients over 50 years old with radiographically confirmed pneumococcal pneumonia (94 bacteremic and 210 nonbacteremic cases) and 608 outpatient control subjects (matched by primary care centre, age, sex and risk stratum). Adjusted odds ratios (ORs) for vaccination were calculated using conditional logistic regression, controlling for underlying conditions. Vaccine effectiveness against all pneumococcal pneumonia was 48% (OR: 0.52; 95% confidence interval [CI]: 0.37-0.73). Vaccination was effective against bacteremic cases (OR: 0.34; 95% CI: 0.27-0.66) as well as nonbacteremic cases (OR: 0.58; 95% CI: 0.39-0.86). Vaccine effectiveness was highest against bacteremic infections caused by vaccine types (OR: 0.24; 95% CI: 0.09-0.66). These findings confirm the effectiveness of the vaccine against invasive disease, but they also support the benefit of vaccination in preventing nonbacteremic pneumococcal pneumonia.

The aim of this study was to investigate the incidence of invasive pneumococcal disease (IPD) in Catalonia. A hospital-based incidence study of the period 1997-1999 was carried out by reviewing the isolations of Streptococcus pneumoniae obtained from normally sterile sites reported by the hospitals that voluntarily participate in the Microbiological Reporting System of Catalonia (MRSC), and those obtained by active retrospective surveillance of cases recorded by microbiology laboratories of the remaining hospitals. Cases of pneumonia were included only if the blood culture was positive. The age, sex and clinical presentation of each patient were recorded. The global incidence of hospital-based IPD was 10.5 per 100,000 persons-year, and was much higher in subjects <2 years of age (59.6) and in those aged > or = 65 years (27.9). In subjects > or = 65 years, bacteremic pneumococcal pneumonias were more frequent in the months from December to March than they were in children <2 years of age (P<0.0001). The global incidence of IPD (10.5 per 100,000 persons-year) is high in Catalonia, greater than that of meningococcal or Haemophilus influenzae invasive disease. In children <2 years, the incidence is nearly six times higher (59.6 per 100,000 persons-year) with pneumonias (rate of 26.2 per 100,000 persons-year) and non-focal bacteremias (rate of 22.1 per 100,000 persons-year) being especially frequent.