Serotype and clonal distribution dynamics of invasive pneumococcal strains after PCV13 introduction

• Published in: PloS one Vol. 15; no. 2; p. e0228612
• Main Authors: Ludwig, Guillermo, Garcia-Garcia, Selene, Lanaspa, Miguel, Ciruela, Pilar, Esteva, Cristina, Fernandez de Sevilla, Mariona, Diaz-Conradi, Alvaro, Marti, Carmina, Motje, Montse, Galles, Carme, Morta, Montse, Izquierdo, Conchita, Moraga-Llop, Fernando, Campins, Magda, Salleras, Luis, Jane, Mireia, Dominguez, Angela, Garcia-Garcia, Juan Jose, Muñoz-Almagro, Carmen
• Format: Journal Article
• Language: English
• Published: Public Library of Science 06-02-2020
• Subjects: Diseases; Intelligence gathering; Pharmaceutical industry; Pneumonia; Setting (Literature); Streptococcus pneumoniae; Vaccination; United States; United Kingdom; Spain
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0228612

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 (65 years) during a period of intermediate PCV13 vaccination coverage (2011-2016) in Catalonia, Spain. 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). 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 65 years. Results found when comparing both periods were consistent with IRRs observed year by year. In children 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. 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.