SARS-CoV-2 RNA loads in breakthrough COVID-19 caused by the Delta and Omicron variants.
OBJECTIVES: To compare SARS-CoV-2 RNA load in nasopharyngeal specimens from patients with breakthrough COVID-19 caused by the Delta or Omicron variants.; METHODS: Retrospective, observational study including 240 consecutive adult out-patients of whom 121 (74 females; median age, 40years) had COVID-1...
| Autores: | , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | INCLIVA |
| Repositorio: | r-INCLIVA. Repositorio Institucional de Producción Científica de INCLIVA |
| OAI Identifier: | oai:incliva.fundanetsuite.com:p16921 |
| Acceso en línea: | https://incliva.portalinvestigacion.com/publicaciones/16921 |
| Access Level: | acceso abierto |
| Palabra clave: | COVID-19 Delta variant Infectious viral load Omicron variant SARS-CoV-2 SARS-CoV-2 RNA load Viability RT-PCR assay |
| Sumario: | OBJECTIVES: To compare SARS-CoV-2 RNA load in nasopharyngeal specimens from patients with breakthrough COVID-19 caused by the Delta or Omicron variants.; METHODS: Retrospective, observational study including 240 consecutive adult out-patients of whom 121 (74 females; median age, 40years) had COVID-19 due to Omicron and 119 (65 females; median age, 48years) caused by the Delta variant. Viral RNA load was quantitated by the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, MS, USA). A viability platinum chloride (PtCl4) RT-PCR assay was used to discriminate between potentially infectious viral particles and free (uncapsidated) viral RNA.; RESULTS: Overall, viral RNA loads were significantly higher (P=0.003) for the Omicron (median, 8.1 log10 copies/ml; range, 4.0-10.9) than the Delta variant (median, 7.5 log10 copies/ml; range, 3.0-11.6). A trend towards higher viral loads was noticed for Omicron compared to Delta across the following time frames since vaccination: days 16-90 (median, 6.83 vs. 5.88 log10 copies/ml; range, 3.91-10.68 vs. 3.67-9.66; P=0.10); days 91-180 (median, 8.09 vs. 7.46 log10 copies/ml; range, 4.30-10.92 vs. 3.03-11.56; P=0.003) and days 181-330 (median, 8.56 vs. 8.10 log10 copies/ml; range, 6.51-10.29 vs. 3.03-10.61; P=0.11). The PtCl4 treated/untreated RT-PCR CT ratio for N target was slightly higher for Omicron than Delta (median, 0.62; range, 0.57-0.98 vs. median, 0.57; range, 0.61-0.87), although statistical significance was not reached (P=0.10).; CONCLUSION: Time elapsed since vaccination has a major impact on SARS-CoV-2 RNA loads in nasopharyngeal specimens, particularly for the Omicron variant. The Omicron variant may be better adapted for replication in the upper respiratory tract than the Delta variant, in which this is unlikely given its more efficient generation of viral particles. Copyright © 2022 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved. |
|---|