{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:53:47Z","timestamp":1792788827505,"version":"4.5.0"},"reference-count":40,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"R\u012bga Stradi\u0146s University","id":[{"id":"https:\/\/ror.org\/03nadks56","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>\n                    <jats:italic>Streptococcus pneumoniae<\/jats:italic>\n                    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\u201318 years at the Children\u2019s 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\n                    <jats:italic>lytA<\/jats:italic>\n                    and\n                    <jats:italic>sp2020<\/jats:italic>\n                    genes; serotyping was performed on PCR-positive samples. Overall carriage prevalence was 21.8% (70\/321; 95% CI: 17.6\u201326.6%). 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\u2014none 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\u2009=\u20090.138). Children aged 1\u20135 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.\n                  <\/jats:p>","DOI":"10.1371\/journal.pone.0359297","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T17:28:30Z","timestamp":1790357310000},"page":"e0359297","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"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"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1196-8407","authenticated-orcid":true,"given":"Hedija","family":"Cupeca","sequence":"first","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Pediatrics"]},{"name":"Children\u2019s Clinical University Hospital of Latvia","place":["Riga, Latvia"],"department":["Department of Pediatrics"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Indra","family":"Zeltina","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Infectology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anita","family":"Villerusa","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Institute of Public Health"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Larisa","family":"Savrasova","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Institute of Public Health"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ilze","family":"Grope","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Pediatrics"]},{"name":"Children\u2019s Clinical University Hospital of Latvia","place":["Riga, Latvia"],"department":["Department of Pediatrics"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maksims","family":"Mukans","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Infectology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3236-2001","authenticated-orcid":true,"given":"Juris","family":"Kibilds","sequence":"additional","affiliation":[{"name":"Institute of Food Safety, Animal Health and Environment BIOR","place":["Riga, Latvia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angelika","family":"Krumina","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Infectology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peteris","family":"Tretjakovs","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Human Physiology and Biochemistry"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ludmila","family":"Viksna","sequence":"additional","affiliation":[{"name":"Riga Stradins University","place":["Riga, Latvia"],"department":["Department of Infectology"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"issue":"9693","key":"pone.0359297.ref001","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1016\/S0140-6736(09)61204-6","article-title":"Burden of disease caused by Streptococcus pneumoniae in children younger than 5 years: global estimates","volume":"374","author":"KL O\u2019Brien","year":"2009","journal-title":"Lancet"},{"issue":"7","key":"pone.0359297.ref002","doi-asserted-by":"crossref","DOI":"10.1016\/S2214-109X(18)30247-X","article-title":"Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: global, regional, and national estimates for 2000-15","volume":"6","author":"B Wahl","year":"2018","journal-title":"Lancet Glob 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