Nationwide trends of invasive pneumococcal disease in Spain (2009-2019) in children and adults during the pneumococcal conjugate vaccine era.

Introduction of pneumococcal conjugate vaccines (PCVs) has shown a marked reduction in the disease caused by vaccine serotypes in children providing herd protection to the elderly group. However, the emergence of non-vaccine serotypes is of great concern worldwide. This study includes national laboratory data from invasive pneumococcal disease (IPD) cases affecting pediatric and adult population during 2009-2019. The impact of implementing different vaccine strategies for immunocompetent adults comparing Spanish regions using PCV13 vs regions using PPV23 vaccine was also analyzed for 2017-2019. The overall reductions of IPD cases by PCV13 serotypes in children and adults were 88% and 59% respectively during 2009-2019 with a constant increase of serotype 8 in adults since 2015. IPD cases by additional serotypes covered by PPV23 increased from 20% in 2009 to 52% in 2019. In children, serotype 24F was the most frequent in 2019 whereas in adults, serotypes 3 and 8 accounted for 36% of IPD cases. Introduction of PCV13 or PPV23 in the adult calendar of certain Spanish regions reduced up to 25% and 11% respectively the IPD cases by PCV13 serotypes, showing a decrease of serotype 3 when PCV13 was used. Use of PCV13 in children has shown a clear impact in pneumococcal epidemiology reducing the burden of IPD in children but also in adults by herd protection although the increase of serotype 8 in adults is worrisome. Vaccination with PCV13 in immunocompetent adults seems to control IPD cases by PCV13 serotypes including serotype 3.This work was supported by Ministerio de Economía, Industria y Competitividad (MINECO) [grant SAF2017-83388] and internal funding fromS

Increase in serotype 19A prevalence and amoxicillin non-susceptibility among paediatric Streptococcus pneumoniae isolates from middle ear fluid in a passive laboratory-based surveillance in Spain, 1997-2009

BACKGROUND: Conjugate vaccines, such as the 7-valent conjugate vaccine (PCV7), alter serotype nasopharyngeal carriage, potentially increasing cases of otitis media by non-vaccine serotypes. METHODS: All paediatric middle ear fluid (MEF) isolates received in the Spanish Reference Laboratory for Pneumococci through a passive, laboratory-based surveillance system from January 1997 to June 2009 were analysed. Data from 1997 to 2000 were pooled as pre-vaccination period. Trends over time were explored by linear regression analysis. RESULTS: A total of 2,077 isolates were analysed: 855 belonging to PCV7 serotypes, 466 to serotype 19A, 215 to serotype 3, 89 to serotype 6A and 452 to other serotypes ( 35% isolates) since PCV7 strains represented < 11% of total clinical isolates. CONCLUSIONS: In contrast to reports on invasive pneumococcal strains, in MEF isolates the reduction in the prevalence of PCV7 serotypes was not associated with decreases in penicillin/erythromycin non-susceptibility. The high prevalence of serotype 19A among paediatric MEF isolates and the amoxicillin non-susceptibility found in this serotype are worrisome since amoxicillin is the most common antibiotic used in the treatment of acute otitis media. These data suggest that non-PCV7 serotypes (mainly serotype 19A followed by serotypes 3 and 6A) are important etiological agents of acute otitis media and support the added value of the broader coverage of the new 13-valent conjugate vaccine.This study was supported in part by an unrestricted grant from Pfizer S.A., Madrid, Spain and PRISM-AG, Madrid, Spain. O.R. belongs to the Spanish Network for the Research in Infectious Diseases (REIPI).S