Vaccination of Icelandic children with the 10-valent pneumococcal vaccine leads to a significant herd effect among adults in Iceland

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Title: Vaccination of Icelandic children with the 10-valent pneumococcal vaccine leads to a significant herd effect among adults in Iceland
Authors: Quirk, SJ
Haraldsson, G
Hjálmarsdóttir, MÁ
Van Tonder, AJ
Hrafnkelsson, B
Bentley, SD
Haraldsson, Á
Erlendsdóttir, H
Brueggemann, AB
Kristinsson, KG
Item Type: Journal Article
Abstract: The introduction of pneumococcal conjugate vaccines (PCV) into childhood vaccination programs has reduced carriage of vaccine serotypes and pneumococcal disease. The 10-valent PCV was introduced in Iceland in 2011. The aim of this study was to determine PCV impact on the prevalence of serotypes, genetic lineages and antimicrobial-resistant pneumococci isolated from the lower respiratory tract (LRT) of adults.Pneumococci isolated during 2009-2017 at the Landspitali University Hospital, were included (n=797). The hospital serves almost three-quarters of the Icelandic population. Isolates were serotyped and tested for antimicrobial susceptibility, and the genome of every other isolate from 2009-2014 was sequenced (n=275). Serotypes and multilocus sequence types (STs) were extracted from the genome data. Three study periods were defined: 2009-2011 (PreVac), 2012-2014 (PostVac-I) and 2015-2017 (PostVac-II).The total number of isolates and vaccine-type (VT) pneumococci decreased from PreVac to PostVac-II (n=314 vs n=230; p=0.002 and n=170 vs n=33; p<0.001, respectively), but nonvaccine-type (NVT) pneumococci increased among adults 18-64 years old (n=56 vs n=114; p=0.008). Serotype 19F decreased in the PostVac-II period: these isolates were all multidrug-resistant (MDR) and were members of the Taiwan19F-14 PMEN lineage. Serotype 6A decreased among adults ≥65 years old PostVac-II (p=0.037), while serotype 6C increased (p=0.021) and most serotype 6C isolates were MDR. Non-encapsulated S. pneumoniae (NESp) increased among adults 18-64 years old PostVac-II and the majority were MDR (p=0.028).An overall reduction in the number of LRT samples, pneumococcal-positive cultures, and significant changes in the serotype distribution became evident within four years thereby demonstrating a significant herd effect.
Issue Date: 28-Mar-2019
Date of Acceptance: 11-Jan-2019
URI: http://hdl.handle.net/10044/1/69272
DOI: https://doi.org/10.1128/JCM.01766-18
ISSN: 0095-1137
Publisher: American Society for Microbiology
Journal / Book Title: Journal of Clinical Microbiology
Volume: 57
Issue: 4
Copyright Statement: © 2019 Quirk et al. This is an openaccess article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/).
Sponsor/Funder: Wellcome Trust
GlaxoSmithKline
Wellcome Trust
John Fell Fund, University of Oxford
Funder's Grant Number: 04992/Z/14/Z
083511/Z/07/Z
Keywords: Science & Technology
Life Sciences & Biomedicine
Microbiology
Iceland
Streptococcus pneumoniae
adults
epidemiology
lower respiratory tract
molecular epidemiology
pneumococcus
pneumonia
vaccination
NONINVASIVE STREPTOCOCCUS-PNEUMONIAE
NONTYPABLE HAEMOPHILUS-INFLUENZAE
COMMUNITY-ACQUIRED PNEUMONIA
ACUTE OTITIS-MEDIA
CONJUGATE VACCINE
SEROTYPE REPLACEMENT
PEDIATRIC-PATIENTS
DISEASE
IMPACT
PCV13
06 Biological Sciences
07 Agricultural and Veterinary Sciences
11 Medical and Health Sciences
Publication Status: Published
Conference Place: United States
Article Number: e01766-18
Online Publication Date: 2019-03-28
Appears in Collections:Department of Medicine
Faculty of Medicine



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