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Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021
BACKGROUND: Increased immune evasion by emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and occurrence of breakthrough infections raise questions about whether coronavirus disease 2019 vaccination status affects SARS-CoV-2 viral load among those infected. This study ex...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10234392/ https://www.ncbi.nlm.nih.gov/pubmed/37274182 http://dx.doi.org/10.1093/ofid/ofad282 |
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author | Ravindran, Saranyah Gubbay, Jonathan B Cronin, Kirby Sullivan, Ashleigh Zygmunt, Austin Johnson, Karen Buchan, Sarah A Parpia, Alyssa S |
author_facet | Ravindran, Saranyah Gubbay, Jonathan B Cronin, Kirby Sullivan, Ashleigh Zygmunt, Austin Johnson, Karen Buchan, Sarah A Parpia, Alyssa S |
author_sort | Ravindran, Saranyah |
collection | PubMed |
description | BACKGROUND: Increased immune evasion by emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and occurrence of breakthrough infections raise questions about whether coronavirus disease 2019 vaccination status affects SARS-CoV-2 viral load among those infected. This study examined the relationship between cycle threshold (Ct) value, which is inversely associated with viral load, and vaccination status at the onset of the Omicron wave onset in Ontario, Canada. METHODS: Using linked provincial databases, we compared median Ct values across vaccination status among polymerase chain reaction–confirmed Omicron variant SARS-CoV-2 cases (sublineages B.1.1.529, BA.1, and BA.1.1) between 6 and 30 December 2021. Cases were presumed to be Omicron based on S-gene target failure. We estimated the relationship between vaccination status and Ct values using multiple linear regression, adjusting for age group, sex, and symptom status. RESULTS: Of the 27 029 presumed Omicron cases in Ontario, the majority were in individuals who had received a complete vaccine series (87.7%), followed by unvaccinated individuals (8.1%), and those who had received a booster dose (4.2%). The median Ct value for post–booster dose individuals (18.3 [interquartile range, 15.4–22.3]) was significantly higher than that for unvaccinated (17.9 [15.2–21.6]; P = .02) and post–vaccine series individuals (17.8 [15.3–21.5]; P = .005). Post–booster dose cases remained associated with a significantly higher median Ct value than cases in unvaccinated individuals (P ≤ .001), after adjustment for covariates. Compared with values in persons aged 18–29 years, Ct values were significantly lower among most age groups >50 years. CONCLUSIONS: While slightly lower Ct values were observed among unvaccinated individuals infected with Omicron compared with post–booster dose cases, further research is required to determine whether a significant difference in secondary transmission exists between these groups. |
format | Online Article Text |
id | pubmed-10234392 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-102343922023-06-02 Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 Ravindran, Saranyah Gubbay, Jonathan B Cronin, Kirby Sullivan, Ashleigh Zygmunt, Austin Johnson, Karen Buchan, Sarah A Parpia, Alyssa S Open Forum Infect Dis Major Article BACKGROUND: Increased immune evasion by emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and occurrence of breakthrough infections raise questions about whether coronavirus disease 2019 vaccination status affects SARS-CoV-2 viral load among those infected. This study examined the relationship between cycle threshold (Ct) value, which is inversely associated with viral load, and vaccination status at the onset of the Omicron wave onset in Ontario, Canada. METHODS: Using linked provincial databases, we compared median Ct values across vaccination status among polymerase chain reaction–confirmed Omicron variant SARS-CoV-2 cases (sublineages B.1.1.529, BA.1, and BA.1.1) between 6 and 30 December 2021. Cases were presumed to be Omicron based on S-gene target failure. We estimated the relationship between vaccination status and Ct values using multiple linear regression, adjusting for age group, sex, and symptom status. RESULTS: Of the 27 029 presumed Omicron cases in Ontario, the majority were in individuals who had received a complete vaccine series (87.7%), followed by unvaccinated individuals (8.1%), and those who had received a booster dose (4.2%). The median Ct value for post–booster dose individuals (18.3 [interquartile range, 15.4–22.3]) was significantly higher than that for unvaccinated (17.9 [15.2–21.6]; P = .02) and post–vaccine series individuals (17.8 [15.3–21.5]; P = .005). Post–booster dose cases remained associated with a significantly higher median Ct value than cases in unvaccinated individuals (P ≤ .001), after adjustment for covariates. Compared with values in persons aged 18–29 years, Ct values were significantly lower among most age groups >50 years. CONCLUSIONS: While slightly lower Ct values were observed among unvaccinated individuals infected with Omicron compared with post–booster dose cases, further research is required to determine whether a significant difference in secondary transmission exists between these groups. Oxford University Press 2023-05-22 /pmc/articles/PMC10234392/ /pubmed/37274182 http://dx.doi.org/10.1093/ofid/ofad282 Text en © The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Major Article Ravindran, Saranyah Gubbay, Jonathan B Cronin, Kirby Sullivan, Ashleigh Zygmunt, Austin Johnson, Karen Buchan, Sarah A Parpia, Alyssa S Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title | Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title_full | Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title_fullStr | Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title_full_unstemmed | Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title_short | Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021 |
title_sort | association between cycle threshold value and vaccination status among severe acute respiratory syndrome coronavirus 2 omicron variant cases in ontario, canada, in december 2021 |
topic | Major Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10234392/ https://www.ncbi.nlm.nih.gov/pubmed/37274182 http://dx.doi.org/10.1093/ofid/ofad282 |
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