{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T07:37:00Z","timestamp":1777534620258,"version":"3.51.4"},"reference-count":19,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,2,4]],"date-time":"2022-02-04T00:00:00Z","timestamp":1643932800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Studies comparing SARS-CoV-2 nasopharyngeal (NP) viral load (VL) according to virus variant and host vaccination status have yielded inconsistent results. We conducted a single center prospective study between July and September 2021 at the drive-through testing center of the Toulouse University Hospital. We compared the NP VL of 3775 patients infected by the Delta (n = 3637) and Alpha (n = 138) variants, respectively. Patient\u2019s symptoms and vaccination status (2619 unvaccinated, 636 one dose and 520 two doses) were recorded. SARS-CoV-2 RNA testing and variant screening were assessed by using Thermo Fisher\u00ae TaqPath\u2122 COVID-19 and ID solutions\u00ae ID\u2122 SARS-CoV-2\/VOC evolution Pentaplex assays. Delta SARS-CoV-2 infections were associated with higher VL than Alpha (coef = 0.68; p \u2264 0.01) independently of patient\u2019s vaccination status, symptoms, age and sex. This difference was higher for patients diagnosed late after symptom onset (coef = 0.88; p = 0.01) than for those diagnosed early (coef = 0.43; p = 0.03). Infections in vaccinated patients were associated with lower VL (coef = \u22120.18; p \u2264 0.01) independently of virus variant, symptom, age and sex. Our results suggest that Delta infections could lead to higher VL and for a longer period compared to Alpha infections. By effectively reducing the NP VL, vaccination could allow for limiting viral spread, even with the Delta variant.<\/jats:p>","DOI":"10.3390\/v14020323","type":"journal-article","created":{"date-parts":[[2022,2,6]],"date-time":"2022-02-06T20:40:18Z","timestamp":1644180018000},"page":"323","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7791-3201","authenticated-orcid":false,"given":"Marion","family":"Migueres","sequence":"first","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"},{"name":"INFINITy (Toulouse Institute for Infectious and Inflammatory Diseases) INSERM UMR1291\/CNRS UMR5051\/Universit\u00e9 Toulouse III, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chlo\u00e9","family":"Dimeglio","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"},{"name":"INFINITy (Toulouse Institute for Infectious and Inflammatory Diseases) INSERM UMR1291\/CNRS UMR5051\/Universit\u00e9 Toulouse III, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pauline","family":"Tr\u00e9meaux","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"St\u00e9phanie","family":"Raymond","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"},{"name":"INFINITy (Toulouse Institute for Infectious and Inflammatory Diseases) INSERM UMR1291\/CNRS UMR5051\/Universit\u00e9 Toulouse III, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7908-1576","authenticated-orcid":false,"given":"S\u00e9bastien","family":"Lhomme","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"},{"name":"INFINITy (Toulouse Institute for Infectious and Inflammatory Diseases) INSERM UMR1291\/CNRS UMR5051\/Universit\u00e9 Toulouse III, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Isabelle","family":"Da Silva","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K\u00e9vin","family":"Oliveira Mendes","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1753-1065","authenticated-orcid":false,"given":"Florence","family":"Abravanel","sequence":"additional","affiliation":[{"name":"Laboratoire de virologie, Institut f\u00e9d\u00e9ratif de Biologie, H\u00f4pital Purpan, Centre Hospitalier Universitaire de Toulouse, 31300 Toulouse, France"},{"name":"INFINITy (Toulouse Institute for Infectious and Inflammatory Diseases) INSERM UMR1291\/CNRS UMR5051\/Universit\u00e9 Toulouse III, 31300 Toulouse, 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