{
  "abstract": "Streptococcus pneumoniae remains a leading cause of invasive disease in children, and nasopharyngeal carriage surveillance is essential for monitoring vaccine-driven changes in serotype distribution. However, carriage data from the Baltic states are scarce. We conducted a cross-sectional study to assess pneumococcal carriage prevalence, serotype distribution, and associated factors in 321 hospitalized children aged 0–18 years at the Children’s Clinical University Hospital of Latvia between January 2021 and September 2022, a period representing the post-PCV13, pre-PCV15/PCV20 era. Pneumococcal carriage was detected by PCR targeting the lytA and sp2020 genes; serotyping was performed on PCR-positive samples. Overall carriage prevalence was 21.8% (70/321; 95% CI: 17.6–26.6%). Of the PCR-positive samples, 78.6% (55/70) were non-typeable and only 21.4% (15/70) yielded identifiable serotypes. Among these 15 typeable isolates, the most frequently detected serotypes were 20, 13, and 48, appearing in complex combinations, followed by 15A/15F, 23B1/23B, and 09N/09L—none of which are covered by PCV13; given the small number of typeable isolates, serotype findings are exploratory. PCV vaccination coverage was 63.2% (203/321), with PCV10 (Synflorix) predominating. No significant association was found between vaccination status and carriage prevalence (vaccinated: 25.6% vs. unvaccinated: 16.7%; p = 0.138). Children aged 1–5 years had the highest carriage prevalence at 30.9%. These data constitute the first comprehensive pneumococcal carriage assessment from the Baltic region during this transitional period and may serve as a reference for evaluating the impact of PCV15 and PCV20 following their introduction.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Pediatrics, Riga Stradins University, Riga, Latvia",
    "Department of Pediatrics, Children’s Clinical University Hospital of Latvia, Riga, Latvia",
    "Department of Infectology, Riga Stradins University, Riga, Latvia",
    "Institute of Public Health, Riga Stradins University, Riga, Latvia",
    "Institute of Food Safety, Animal Health and Environment BIOR, Riga, Latvia",
    "Department of Human Physiology and Biochemistry, Riga Stradins University, Riga, Latvia"
  ],
  "article_type": "Research Article",
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Hedija Cupeca"
    },
    {
      "affs": [
        1
      ],
      "name": "Indra Zeltina"
    },
    {
      "affs": [
        2
      ],
      "name": "Anita Villerusa"
    },
    {
      "affs": [
        3
      ],
      "name": "Larisa Savrasova"
    },
    {
      "affs": [
        4
      ],
      "name": "Ilze Grope"
    },
    {
      "affs": [
        5
      ],
      "name": "Maksims Mukans"
    },
    {
      "name": "Juris Kibilds"
    },
    {
      "name": "Angelika Krumina"
    },
    {
      "name": "Peteris Tretjakovs"
    },
    {
      "name": "Ludmila Viksna"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ech77bn4b7890.bib",
  "cited_by": 0,
  "doi": "10.1371/journal.pone.0359297",
  "fulltext_url": null,
  "id": "ech77bn4b7890",
  "issns": [
    "1932-6203"
  ],
  "landing_url": "https://doi.org/10.1371/journal.pone.0359297",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2713|Pneumonia and Respiratory Infections"
    ],
    [
      "plos",
      "/Biology and life sciences/Immunology/Vaccination and immunization"
    ],
    [
      "plos",
      "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Bacterial pathogens/Streptococcus/Pneumococcus"
    ],
    [
      "plos",
      "/Biology and life sciences/Microbiology/Microbial control/Antimicrobials/Antibiotics"
    ],
    [
      "plos",
      "/Biology and life sciences/Organisms/Bacteria/Streptococcus/Pneumococcus"
    ],
    [
      "plos",
      "/Medicine and health sciences/Epidemiology/Disease surveillance"
    ],
    [
      "plos",
      "/Medicine and health sciences/Immunology/Vaccination and immunization"
    ],
    [
      "plos",
      "/Medicine and health sciences/Medical conditions/Infectious diseases/Infectious disease control/Vaccines"
    ],
    [
      "plos",
      "/Medicine and health sciences/Medical conditions/Infectious diseases/Viral diseases/COVID 19"
    ],
    [
      "plos",
      "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Bacterial pathogens/Streptococcus/Pneumococcus"
    ],
    [
      "plos",
      "/Medicine and health sciences/Pharmacology/Drugs/Antimicrobials/Antibiotics"
    ],
    [
      "plos",
      "/Medicine and health sciences/Public and occupational health/Preventive medicine/Vaccination and immunization"
    ],
    [
      "plos",
      "/People and places/Geographical locations/Europe/European Union/Latvia"
    ],
    [
      "plos",
      "/People and places/Population groupings/Age groups"
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  "pdf_url": "https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0359297&type=printable",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-25",
  "publisher": "Public Library of Science",
  "ris": "https://research.draconitic.com/paper/ech77bn4b7890.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:43Z",
      "native_id": "10.1371/journal.pone.0359297",
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      "url": "https://doi.org/10.1371/journal.pone.0359297"
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  "subjects": [
    {
      "field": "biology",
      "origin": "plos:immunology",
      "subfield": "immunology"
    },
    {
      "field": "biology",
      "origin": "plos:microbiology",
      "subfield": "microbiology"
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    {
      "field": "medicine",
      "origin": "plos:epidemiology",
      "subfield": "epidemiology-public-health"
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  "title": "Pneumococcal nasopharyngeal carriage, serotype distribution, and vaccination status in hospitalized children in Latvia: A cross-sectional study during the post-PCV13, pre-PCV15/PCV20 transition period",
  "title_text": "Pneumococcal nasopharyngeal carriage, serotype distribution, and vaccination status in hospitalized children in Latvia: A cross-sectional study during the post-PCV13, pre-PCV15/PCV20 transition period",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:43Z",
  "url": "https://research.draconitic.com/paper/ech77bn4b7890",
  "venue": "PLOS One",
  "versions": []
}