title: Effects of PCV7 and PCV13 on invasive pneumococcal disease and carriage in Stockholm, Sweden.
abstract: The effects of pneumococcal conjugated vaccines (PCVs) need to be investigated. In Stockholm County, Sweden, PCV7 was introduced in the childhood immunisation programme in 2007 and changed to PCV13 in 2010.Over 90% of all invasive isolates during 2005-2014 (n=2336) and carriage isolates, 260 before and 647 after vaccine introduction, were characterised by serotyping, molecular typing and antibiotic susceptibility, and serotype diversity was calculated. Clinical information was collected for children and adults with invasive pneumococcal disease (IPD).The IPD incidence decreased post-PCV7, but not post-PCV13, in vaccinated children. Beneficial herd effects were seen in older children and adults, but not in the elderly. The herd protection was more pronounced post-PCV7 than post-PCV13. PCV7 serotypes decreased. IPD caused by PCV13 serotypes 3 and 19A increased post-PCV7. Post-PCV13, serotypes 6A and 19A, but not serotype 3, decreased. The serotype distribution changed in carriage and IPD to nonvaccine types, also in nonvaccinated populations. Expansion of non-PCV13 serotypes was largest following PCV13 introduction. Serotype diversity increased and nonvaccine clones emerged, such as CC433 (serotype 22F) in IPD and CC62 (serotype 11A) in carriage. In young children, meningitis, septicaemia and severe rhinosinusitis, but not bacteraemic pneumonia, decreased.Pneumococcal vaccination leads to expansion of new or minor serotypes/clones, also in nonvaccinated populations.
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden These authors contributed equally to this article.
authors.forename: Ilias
authors.initials: I
authors.lastname: Galanis
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden Dept of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden These authors contributed equally to this article.
authors.forename: Ann
authors.initials: A
authors.lastname: Lindstrand
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden These authors contributed equally to this article.
authors.forename: Jessica
authors.initials: J
authors.lastname: Darenberg
authors.affiliation: Dept of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden Dept of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Sarah
authors.initials: S
authors.lastname: Browall
authors.affiliation: Dept of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Nannapaneni
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Sjöström
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Morfeldt
authors.affiliation: Dept of Medicine Solna, Infectious Diseases Unit, Karolinska Institutet, Stockholm, Sweden Dept of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Pontus
authors.initials: P
authors.lastname: Naucler
authors.affiliation: Sachs' Children's Hospital, South General Hospital, Stockholm, Sweden Dept of Clinical Sciences and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Margareta
authors.initials: M
authors.lastname: Blennow
authors.affiliation: Dept of Medicine Solna, Infectious Diseases Unit, Karolinska Institutet, Stockholm, Sweden Dept of Clinical Science and Education Södersjukhuset, Karolinska Institutet, Stockholm, Sweden These authors contributed equally to this article.
authors.forename: Åke
authors.initials: Å
authors.lastname: Örtqvist
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden Dept of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden Dept of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden These authors contributed equally to this article birgitta.henriques@ki.se.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Henriques-Normark
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000627:therapeutic use*; D006801:Humans; D032521:Immunity, Herd; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification*; D013548:Sweden; D018074:Vaccines, Conjugate / Q000627:therapeutic use; D055815:Young Adult
chemical_list: C538862:13-valent pneumococcal vaccine; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate