{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T17:31:20Z","timestamp":1773423080178,"version":"3.50.1"},"reference-count":57,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,3,28]],"date-time":"2024-03-28T00:00:00Z","timestamp":1711584000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Senate of Berlin"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>SARS-CoV-2 serology may be helpful to retrospectively understand infection dynamics in specific settings including kindergartens. We assessed SARS-CoV-2 seroprevalence in individuals connected to kindergartens in Berlin, Germany in September 2021. Children, staff, and household members from 12 randomly selected kindergartens were interviewed on COVID-19 history and sociodemographic parameters. Blood samples were collected on filter paper. SARS-CoV-2 anti-S and anti-N antibodies were assessed using Roche Elecsys. We assessed seroprevalence and the proportion of so far unrecognized SARS-CoV-2 infections. We included 277 participants, comprising 48 (17.3%) kindergarten children, 37 (13.4%) staff, and 192 (69.3%) household members. SARS-CoV-2 antibodies were present in 65.0%, and 52.7% of all participants were vaccinated. Evidence of previous infection was observed in 16.7% of kindergarten children, 16.2% of staff, and 10.4% of household members. Undiagnosed infections were observed in 12.5%, 5.4%, and 3.6%, respectively. Preceding infections were associated with facemask neglect. In conclusion, two-thirds of our cohort were SARS-CoV-2 seroreactive in September 2021, largely as a result of vaccination in adults. Kindergarten children showed the highest proportion of non-vaccine-induced seropositivity and an increased proportion of previously unrecognized SARS-CoV-2 infection. Silent infections in pre-school children need to be considered when interpreting SARS-CoV-2 infections in the kindergarten context.<\/jats:p>","DOI":"10.3390\/children11040405","type":"journal-article","created":{"date-parts":[[2024,3,28]],"date-time":"2024-03-28T12:52:12Z","timestamp":1711630332000},"page":"405","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["SARS-CoV-2 Seroprevalence in a Berlin Kindergarten Environment: A Cross-Sectional Study, September 2021"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-8970-5641","authenticated-orcid":false,"given":"Julian","family":"Bernhard","sequence":"first","affiliation":[{"name":"Institute of International Health, Charit\u00e9 Center for Global Health, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5372-7903","authenticated-orcid":false,"given":"Stefanie","family":"Theuring","sequence":"additional","affiliation":[{"name":"Institute of International Health, Charit\u00e9 Center for Global Health, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Welmoed","family":"van Loon","sequence":"additional","affiliation":[{"name":"Institute of International Health, Charit\u00e9 Center for Global Health, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4057-2199","authenticated-orcid":false,"given":"Marcus A.","family":"Mall","sequence":"additional","affiliation":[{"name":"Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 13353 Berlin, Germany"},{"name":"Berlin Institute of Health (BIH) at Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, 13353 Berlin, Germany"},{"name":"German Centre for Lung Research (DZL), 35392 Gie\u00dfen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1444-8976","authenticated-orcid":false,"given":"Joachim","family":"Seybold","sequence":"additional","affiliation":[{"name":"Medical Directorate, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7169-2620","authenticated-orcid":false,"given":"Tobias","family":"Kurth","sequence":"additional","affiliation":[{"name":"Institute of Public Health, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Raquel","family":"Rubio-Acero","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases and Tropical Medicine, Ludwig-Maximilians-Universit\u00e4t, 80802 Munich, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreas","family":"Wieser","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases and Tropical Medicine, Ludwig-Maximilians-Universit\u00e4t, 80802 Munich, Germany"},{"name":"Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Ludwig-Maximilians-Universit\u00e4t, 80336 Munich, Germany"},{"name":"German Centre for Infection Research (DZIF), 80802 Munich, Germany"},{"name":"Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), 80779 Munich, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8117-5421","authenticated-orcid":false,"given":"Frank P.","family":"Mockenhaupt","sequence":"additional","affiliation":[{"name":"Institute of International Health, Charit\u00e9 Center for Global Health, Charit\u00e9\u2014Universit\u00e4tsmedizin Berlin, Corporate Member of Freie Universit\u00e4t Berlin and Humboldt-Universit\u00e4t zu Berlin, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e2020031971","DOI":"10.1542\/peds.2020-031971","article-title":"COVID-19 Transmission in US Child Care Programs","volume":"147","author":"Gilliam","year":"2021","journal-title":"Pediatrics"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2001587","DOI":"10.2807\/1560-7917.ES.2020.25.36.2001587","article-title":"Transmission of SARS-CoV-2 in children aged 0 to 19 years in childcare facilities and schools after their reopening in May 2020, Baden-W\u00fcrttemberg, Germany","volume":"25","author":"Ehrhardt","year":"2020","journal-title":"Eurosurveillance"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1105","DOI":"10.1093\/eurpub\/ckab079","article-title":"SARS-CoV-2 infections in kindergartens and associated households at the start of the second wave in Berlin, Germany\u2014A cross-sectional study","volume":"31","author":"Thielecke","year":"2021","journal-title":"Eur. J. Public Health"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1525","DOI":"10.1111\/apa.15371","article-title":"Children are unlikely to be the main drivers of the COVID-19 pandemic\u2014A systematic review","volume":"109","author":"Ludvigsson","year":"2020","journal-title":"Acta Paediatr."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"E810","DOI":"10.9778\/cmajo.20210106","article-title":"SARS-CoV-2 transmission in kindergarten to grade 12 schools in the Vancouver Coastal Health region: A descriptive epidemiologic study","volume":"9","author":"Bark","year":"2021","journal-title":"CMAJ Open"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1007\/s00112-021-01134-8","article-title":"Children and COVID-19-Data from mandatory reporting and results of contact person testing in daycare centers and schools in Frankfurt am Main, Germany, August\u2013December 2020","volume":"169","author":"Heudorf","year":"2021","journal-title":"Monatsschrift Kinderheilkd."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e172","DOI":"10.1097\/INF.0000000000003497","article-title":"The Role of Children and Young People in the Transmission of SARS-CoV-2","volume":"41","author":"Strenger","year":"2022","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1001\/jamapediatrics.2020.4573","article-title":"Susceptibility to SARS-CoV-2 Infection Among Children and Adolescents Compared with Adults: A systematic review and meta-analysis","volume":"175","author":"Viner","year":"2021","journal-title":"JAMA Pediatr."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1663","DOI":"10.1056\/NEJMc2005073","article-title":"SARS-CoV-2 Infection in Children","volume":"382","author":"Lu","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.medj.2020.10.003","article-title":"A Public Health Antibody Screening Indicates a 6-Fold Higher SARS-CoV-2 Exposure Rate than Reported Cases in Children","volume":"2","author":"Hippich","year":"2020","journal-title":"Med"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1016\/j.medj.2021.03.019","article-title":"A public health antibody screening indicates a marked increase of SARS-CoV-2 exposure rate in children during the second wave","volume":"2","author":"Hippich","year":"2021","journal-title":"Med"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"957","DOI":"10.3390\/idr13040088","article-title":"Longitudinal Rise in Seroprevalence of SARS-CoV-2 Infections in Children in Western Germany\u2014A Blind Spot in Epidemiology?","volume":"13","author":"Brinkmann","year":"2021","journal-title":"Infect. Dis. Rep."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Ruf, S., Hommes, F., van Loon, W., Seybold, J., Kurth, T., Mall, M.A., Mockenhaupt, F.P., and Theuring, S. (2021). A Retrospective Outbreak Investigation of a COVID-19 Case Cluster in a Berlin Kindergarten, November 2020. Int. J. Environ. Res. Public Health, 19.","DOI":"10.3390\/ijerph19010036"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1110","DOI":"10.1001\/jamapediatrics.2021.2767","article-title":"Yes, Children Can Transmit COVID, but We Need Not Fear","volume":"175","author":"Coffin","year":"2021","journal-title":"JAMA Pediatr."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1007\/s10875-022-01355-w","article-title":"Long-Term Antibody Response to SARS-CoV-2 in Children","volume":"43","author":"Dunay","year":"2022","journal-title":"J. Clin. Immunol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2100524","DOI":"10.2807\/1560-7917.ES.2022.27.11.2100524","article-title":"SARS-CoV-2 infection among educational staff in Berlin, Germany, June to December 2020","volume":"27","author":"Kindzierski","year":"2022","journal-title":"Eurosurveillance"},{"key":"ref_17","unstructured":"RKI (2022, November 09). Epidemiologisches Bulletin 10_2022: Robert Koch Institute Germany; 2022. Available online: https:\/\/www.rki.de\/DE\/Content\/Infekt\/EpidBull\/Archiv\/2022\/Ausgaben\/10_22.pdf?__blob=publicationFile."},{"key":"ref_18","unstructured":"Bundesregierung (2022, November 16). Infektionsschutzgesetz\u2014Vierte Gesetz Zum Schutz Der Bev\u00f6lkerung Bei Einer Epidemischen Lage Von Nationaler Tragweite Bundesgesetzblatt Jahrgang 2021 Teil I Nr. 18, ausgegeben zu Bonn am 22. April 2021, Available online: https:\/\/www.bundesgesundheitsministerium.de\/fileadmin\/Dateien\/3_Downloads\/Gesetze_und_Verordnungen\/GuV\/B\/4_BevSchG_BGBL.pdf."},{"key":"ref_19","unstructured":"LAGeSo LfGuSB (2022, November 16). COVID-19 in Berlin, Fallzahlen und Indikatoren\u2014Gesamt\u00fcbersicht: Landesamt f\u00fcr Gesundheit und Soziales Berlin LAGeSo. Available online: https:\/\/daten.berlin.de\/datensaetze\/covid-19-berlin-fallzahlen-und-indikatoren-gesamt%C3%BCbersicht."},{"key":"ref_20","unstructured":"RKI (2022, November 16). Epidemiologisches Bulletin 23_2021: Robert Koch Institute Germany. Available online: https:\/\/www.rki.de\/DE\/Content\/Infekt\/EpidBull\/Archiv\/2021\/Ausgaben\/23_21.pdf?__blob=publicationFile."},{"key":"ref_21","unstructured":"RKI (2022, November 09). W\u00f6chentlicher Lagebericht Des Rki Zur Coronavirus-Krankheit-2019 (COVID-19) 38_2021: Robert Koch Institute Germany. Available online: https:\/\/www.rki.de\/DE\/Content\/InfAZ\/N\/Neuartiges_Coronavirus\/Situationsberichte\/Wochenbericht\/Wochenbericht_2021-09-30.pdf?__blob=publicationFile."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Harris, P.A., Taylor, R., Minor, B.L., Elliott, V., Fernandez, M., O\u2019Neal, L., McLeod, L., Delacqua, G., Delacqua, F., and Kirby, J. (2019). The REDCap consortium: Building an international community of software platform partners. J. Biomed. Inform., 95.","DOI":"10.1016\/j.jbi.2019.103208"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Beyerl, J., Rubio-Acero, R., Castelletti, N., Paunovic, I., Kroidl, I., Khan, Z.N., Bakuli, A., Tautz, A., Oft, J., and Hoelscher, M. (2021). A dried blood spot protocol for high throughput analysis of SARS-CoV-2 serology based on the Roche Elecsys anti-N assay. EBioMedicine, 70.","DOI":"10.1016\/j.ebiom.2021.103502"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"105052","DOI":"10.1016\/j.jcv.2021.105052","article-title":"Antibody response to SARS-CoV-2 for more than one year\u2014Kinetics and persistence of detection are predominantly determined by avidity progression and test design","volume":"146","author":"Scheiblauer","year":"2022","journal-title":"J. Clin. Virol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1505","DOI":"10.1007\/s40121-021-00475-x","article-title":"In Search of the SARS-CoV-2 Protection Correlate: Head-to-Head Comparison of Two Quantitative S1 Assays in Pre-characterized Oligo-\/Asymptomatic Patients","volume":"10","author":"Castelletti","year":"2021","journal-title":"Infect. Dis. Ther."},{"key":"ref_26","unstructured":"(2022, November 16). Available online: https:\/\/www.ibm.com\/analytics\/spss-statistics-software."},{"key":"ref_27","first-page":"765","article-title":"SARS-CoV-2 Seroprevalence in Preschool and School-Age Children","volume":"119","author":"Ott","year":"2022","journal-title":"Dtsch. Aerzteblatt Online"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2101028","DOI":"10.2807\/1560-7917.ES.2022.27.37.2101028","article-title":"Seroconversion rate and socio-economic and ethnic risk factors for SARS-CoV-2 infection in children in a population-based cohort, Germany, June 2020 to February 2021","volume":"27","author":"Brinkmann","year":"2022","journal-title":"Eurosurveillance"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3128","DOI":"10.1038\/s41467-022-30482-6","article-title":"Cross-sectional seroprevalence surveys of SARS-CoV-2 antibodies in children in Germany, June 2020 to May 2021","volume":"13","author":"Sorg","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/S2352-4642(21)00024-9","article-title":"SARS-CoV-2 transmission among children and staff in daycare centres during a nationwide lockdown in France: A cross-sectional, multicentre, seroprevalence study","volume":"5","author":"Lachassinne","year":"2021","journal-title":"Lancet Child Adolesc. Health"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e141","DOI":"10.1017\/S0950268822001194","article-title":"Transmission of SARS-CoV-2 among children and staff in German daycare centres","volume":"150","author":"Loss","year":"2022","journal-title":"Epidemiol. Infect."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Koh, W.C., Naing, L., Chaw, L., Rosledzana, M.A., Alikhan, M.F., Jamaludin, S.A., Amin, F., Omar, A., Shazli, A., and Griffith, M. (2020). What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors. PLoS ONE, 15.","DOI":"10.1101\/2020.05.21.20108746"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1016\/j.ijid.2022.05.016","article-title":"The role of children in household transmission of COVID-19: A systematic review and meta-analysis","volume":"122","author":"Chen","year":"2022","journal-title":"Int. J. Infect. Dis."},{"key":"ref_34","unstructured":"RKI (2022, November 13). SurvStat@RKI Abfrage Der Meldedaten Nach Infektionsschutzgesetz (IfSG) \u00dcber Das Web: Robert Koch Institute Germany. Available online: https:\/\/www.rki.de\/DE\/Content\/Infekt\/SurvStat\/survstat_node.html."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1080\/20469047.2021.1888026","article-title":"Update on SARS-CoV-2 infection in children","volume":"41","author":"Martins","year":"2021","journal-title":"Paediatr. Int. Child Health"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1016\/S2352-4642(20)30177-2","article-title":"COVID-19 in children and adolescents in Europe: A multinational, multicentre cohort study","volume":"4","author":"Lanaspa","year":"2020","journal-title":"Lancet Child Adolesc. Health"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"530","DOI":"10.47102\/annals-acadmedsg.2020257","article-title":"Comparative Analysis of Symptomatic and Asymptomatic SARS-CoV-2 Infection in Children","volume":"49","author":"Li","year":"2020","journal-title":"Ann. Acad. Med. Singap."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1142","DOI":"10.1001\/jamapediatrics.2022.3072","article-title":"Analysis of Neutralizing Antibody Levels in Children and Adolescents Up to 16 Months After SARS-CoV-2 Infection","volume":"176","author":"Yung","year":"2022","journal-title":"JAMA Pediatr."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"e2227348","DOI":"10.1001\/jamanetworkopen.2022.27348","article-title":"Assessment of Clinical and Virological Characteristics of SARS-CoV-2 Infection Among Children Aged 0 to 4 Years and Their Household Members","volume":"5","author":"Karron","year":"2022","journal-title":"JAMA Netw. Open"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e2227357","DOI":"10.1001\/jamanetworkopen.2022.27357","article-title":"How Do We Stop the Spread of SARS-CoV-2 in Young Children?","volume":"5","author":"Kim","year":"2022","journal-title":"JAMA Netw. Open"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1016\/j.pathol.2020.08.001","article-title":"SARS-CoV-2 in children: Spectrum of disease, transmission and immunopathological underpinnings","volume":"52","author":"Williams","year":"2020","journal-title":"Pathology"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1007\/s12519-022-00553-1","article-title":"Gastrointestinal viral shedding in children with SARS-CoV-2: A systematic review and meta-analysis","volume":"18","author":"Benvari","year":"2022","journal-title":"World J. Pediatr."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"e133","DOI":"10.1097\/INF.0000000000002704","article-title":"Fecal-Oral Transmission of SARS-CoV-2 In Children: Is it Time to Change Our Approach?","volume":"39","author":"Minotti","year":"2020","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"e28318","DOI":"10.1002\/jmv.28318","article-title":"SARS-CoV-2 infection in children evaluated in an ambulatory setting during Delta and Omicron time periods","volume":"95","author":"Smith","year":"2023","journal-title":"J. Med. Virol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"998","DOI":"10.1001\/jama.2021.1505","article-title":"Effectiveness of Mask Wearing to Control Community Spread of SARS-CoV-2","volume":"325","author":"Brooks","year":"2021","journal-title":"JAMA"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Howard, J., Huang, A., Li, Z., Tufekci, Z., Zdimal, V., van der Westhuizen, H.-M., von Delft, A., Price, A., Fridman, L., and Tang, L.-H. (2021). An evidence review of face masks against COVID-19. Proc. Natl. Acad. Sci. USA, 118.","DOI":"10.1073\/pnas.2014564118"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"900","DOI":"10.1016\/j.ajic.2020.12.007","article-title":"Face masks to prevent transmission of COVID-19: A systematic review and meta-analysis","volume":"49","author":"Li","year":"2020","journal-title":"Am. J. Infect. Control."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"e148","DOI":"10.1016\/S2589-7500(20)30293-4","article-title":"Mask-wearing and control of SARS-CoV-2 transmission in the USA: A cross-sectional study","volume":"3","author":"Rader","year":"2021","journal-title":"Lancet Digit. Health"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"e00637-20","DOI":"10.1128\/mSphere.00637-20","article-title":"Effectiveness of Face Masks in Preventing Airborne Transmission of SARS-CoV-2","volume":"5","author":"Ueki","year":"2020","journal-title":"mSphere"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2333794x221085385","DOI":"10.1177\/2333794X221085385","article-title":"Seroprevalence of SARS-CoV-2 Antibodies in Children and Adolescents: Results from a Population-Based Survey in 10 Colombian Cities","volume":"9","author":"Daza","year":"2022","journal-title":"Glob. Pediatr. Health"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"110796","DOI":"10.1016\/j.envres.2021.110796","article-title":"The use of dried blood spots for characterizing children\u2019s exposure to organic environmental chemicals","volume":"195","author":"Barr","year":"2021","journal-title":"Environ. Res."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Ostler, M.W., Porter, J.H., and Buxton, O.M. (2014). Dried Blood Spot Collection of Health Biomarkers to Maximize Participation in Population Studies. J. Vis. Exp., e50973.","DOI":"10.3791\/50973-v"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"e0133020","DOI":"10.1128\/mSphere.01330-20","article-title":"Diagnostic Accuracy of Dried Blood Spots Collected on HemaSpot HF Devices Compared to Venous Blood Specimens to Estimate Measles and Rubella Seroprevalence","volume":"6","author":"Prosperi","year":"2021","journal-title":"mSphere"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"104739","DOI":"10.1016\/j.jcv.2021.104739","article-title":"Use of dried blood spot samples for SARS-CoV-2 antibody detection using the Roche Elecsys\u00ae high throughput immunoassay","volume":"136","author":"Mulchandani","year":"2021","journal-title":"J. Clin. Virol."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"M\u00e9ndez-Echevarr\u00eda, A., Sainz, T., Falces-Romero, I., de Felipe, B., Escolano, L., Alcolea, S., Perti\u00f1ez, L., Neth, O., and Calvo, C. (2021). Long-Term Persistence of Anti-SARS-CoV-2 Antibodies in a Pediatric Population. Pathogens, 10.","DOI":"10.3390\/pathogens10060700"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"e294","DOI":"10.1097\/INF.0000000000003199","article-title":"Longitudinal Follow-up of Antibody Responses in Pediatric Patients with COVID-19 up to 9 Months After Infection","volume":"40","author":"Oygar","year":"2021","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_57","first-page":"771","article-title":"High seroprevalence of SARS-CoV-2 in preschool children in July 2022\u2014A cross-sectional data collection in day-care centers","volume":"119","author":"Engels","year":"2022","journal-title":"Dtsch. Arztebl. Int."}],"container-title":["Children"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9067\/11\/4\/405\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:20:24Z","timestamp":1760106024000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9067\/11\/4\/405"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,3,28]]},"references-count":57,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2024,4]]}},"alternative-id":["children11040405"],"URL":"https:\/\/doi.org\/10.3390\/children11040405","relation":{},"ISSN":["2227-9067"],"issn-type":[{"value":"2227-9067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,3,28]]}}}