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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...

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Autores principales: Ravindran, Saranyah, Gubbay, Jonathan B, Cronin, Kirby, Sullivan, Ashleigh, Zygmunt, Austin, Johnson, Karen, Buchan, Sarah A, Parpia, Alyssa S
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2023
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.
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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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