Misinterpretation of viral load in COVID-19

Miranda, Renan Lyra; Guterres, Alexandro; Lima, Carlos Henrique de Azeredo; Filho, Paulo Niemeyer; Gadelha, Mônica R.

doi:10.1101/2020.10.06.20208009

Cited by 5 publications

(5 citation statements)

References 24 publications

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“…There are however considerable limitations in the use of CT values for prognostication and treatment planning at the level of individual patients. Critics have noted that there may be significant variability in CT values based on the quantity of biological material collected on a testing swab as well as differences in RT-PCR reagents, equipment, and standards among laboratories [ 21 ]. CT values may also vary based on the gene target selected for RT-PCR or even based on the assay used to detect the same gene target [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

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Correlation of Population SARS-CoV-2 Cycle Threshold Values to Local Disease Dynamics: Exploratory Observational Study

Tso¹,

Garikipati²,

Green‐Saxena³

et al. 2021

JMIR Public Health Surveill

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Background Despite the limitations in the use of cycle threshold (CT) values for individual patient care, population distributions of CT values may be useful indicators of local outbreaks. Objective We aimed to conduct an exploratory analysis of potential correlations between the population distribution of cycle threshold (CT) values and COVID-19 dynamics, which were operationalized as percent positivity, transmission rate (Rt), and COVID-19 hospitalization count. Methods In total, 148,410 specimens collected between September 15, 2020, and January 11, 2021, from the greater El Paso area were processed in the Dascena COVID-19 Laboratory. The daily median CT value, daily Rt, daily count of COVID-19 hospitalizations, daily change in percent positivity, and rolling averages of these features were plotted over time. Two-way scatterplots and linear regression were used to evaluate possible associations between daily median CT values and outbreak measures. Cross-correlation plots were used to determine whether a time delay existed between changes in daily median CT values and measures of community disease dynamics. Results Daily median CT values negatively correlated with the daily Rt values (P<.001), the daily COVID-19 hospitalization counts (with a 33-day time delay; P<.001), and the daily changes in percent positivity among testing samples (P<.001). Despite visual trends suggesting time delays in the plots for median CT values and outbreak measures, a statistically significant delay was only detected between changes in median CT values and COVID-19 hospitalization counts (P<.001). Conclusions This study adds to the literature by analyzing samples collected from an entire geographical area and contextualizing the results with other research investigating population CT values.

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Section: Introductionmentioning

confidence: 99%

“…CT values, when used as a semiquantitative measure of how much viral nucleic acid is present, are similarly limited. As a result of these constraints, clinicians and researchers continue to debate the utility of CT values for informing health care choices for individuals [ 5 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Correlation of Population SARS-CoV-2 Cycle Threshold Values to Local Disease Dynamics: Exploratory Observational Study

Tso¹,

Garikipati²,

Green‐Saxena³

et al. 2021

JMIR Public Health Surveill

View full text Add to dashboard Cite

show abstract

“…In our study, the difference between positive control Ct value and sample Ct value (ΔCt) was used to normalize the estimation of viral loads to minimize the variation among different runs. 10 11 Calculated ΔCt values were inversely related to viral RNA copy numbers for SARS-CoV-2.…”

Section: Methodsmentioning

confidence: 99%

The Impact of Alpha Variant (B.1.1.7), Viral Load, and Age on the Clinical Course of Pediatric COVID-19 Patients

Unalan-Altintop

Celep

Milletli-Sezgin

et al. 2022

J Pediatr Infect Dis

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Objective The research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mainly consists of adult patients, leaving its impact on children understudied. This study aims to investigate the correlations between viral load, clinical course, age, and Alpha variant (B.1.1.7) in children. Methods The study was conducted on children under the age of 18 years, who were admitted to Amasya University Sabuncuoglu Serefeddin Research and Training Hospital in Turkey between February and April 2021. ΔCt values, which were obtained by real-time polymerase chain reaction (PCR), were analyzed to estimate the viral loads of the patients. Alpha variant (B.1.1.7) positivity was determined by real-time PCR. Results There was no difference between estimated viral loads of different clinical courses (p > 0.05), or between asymptomatic and symptomatic patients (p > 0.05). Viral loads were found to decrease with increasing age (p = 0.002). Also, a higher rate of symptomatic disease was found in children under the age of 4 years (p < 0.05). Alpha variant (B.1.1.7) was not found to be associated with severe disease in children (p > 0.05). Conclusion Our results demonstrate higher viral loads and symptomatic disease in children under the age of 4 years. Alpha variant (B.1.1.7) was not found to be related to disease severity. There has not been a consensus on the vaccination of the pediatric population worldwide. More studies are needed to understand the viral kinetics of SARS-CoV-2 and its severity on children to build effective vaccination strategies in children as public health restrictions are eased.

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“…However, there are significant limitations to the use of CT values for prognostication and treatment planning at the level of the individual patient. Critics have noted that there may be significant variability in CT values based on the quantity of biological material collected on a testing swab, as well differences in RT-PCR reagents, equipment and standards between laboratories (21). CT values may also vary based on the gene target selected for RT-PCR, or even on the assay used to detect the same gene target (22).…”

Section: Introductionmentioning

confidence: 99%

“…As a result of these constraints, clinicians and researchers continue to debate the utility of CT values for informing healthcare choices for individuals (e.g. (5,21,22)).…”

Section: Introductionmentioning

confidence: 99%

An exploratory study on the correlation of population SARS-CoV-2 cycle threshold values to local disease dynamics

Tso

Garikipati

Green‐Saxena

et al. 2021

Preprint

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Introduction: Despite limitations on the use of cycle threshold (CT) values for individual patient care, population distributions of CT values may be useful indicators of local outbreaks. Methods: Specimens from the greater El Paso area were processed in the Dascena COVID-19 Laboratory. Daily median CT value, daily transmission rate R(t), daily count of COVID-19 hospitalizations, daily change in percent positivity, and rolling averages of these features were plotted over time. Two-way scatterplots and linear regression evaluated possible associations between daily median CT and outbreak measures. Cross-correlation plots determined whether a time delay existed between changes in the daily median CT value and measure of community disease dynamics. Results: Daily median CT was negatively correlated with the daily R(t), the daily COVID-19 hospitalization count (with a time delay), and the daily change in percent positivity among testing samples. Despite visual trends suggesting time delays in the plots for median CT and outbreak measures, a statistically significant delay was only detected between changes in median CT and COVID-19 hospitalization count. Conclusions: This study adds to the literature by analyzing samples collected from an entire geographical area, and contextualizing the results with other research investigating population CT values.

show abstract

Misinterpretation of viral load in COVID-19

Cited by 5 publications

References 24 publications

Correlation of Population SARS-CoV-2 Cycle Threshold Values to Local Disease Dynamics: Exploratory Observational Study

Correlation of Population SARS-CoV-2 Cycle Threshold Values to Local Disease Dynamics: Exploratory Observational Study

The Impact of Alpha Variant (B.1.1.7), Viral Load, and Age on the Clinical Course of Pediatric COVID-19 Patients

An exploratory study on the correlation of population SARS-CoV-2 cycle threshold values to local disease dynamics

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