SARS-CoV-2 variants of concern are associated with lower RT-PCR amplification cycles between January and March 2021 in France

Roquebert, Bénédicte; Haïm-Boukobza, Stéphanie; Trombert‐Paolantoni, Sabine; Lecorché, Emmanuel; Verdurme, Laura; Foulongne, Vincent; Burrel, Sonia; Alizon, Samuel; Sofonea, Mircea T.

doi:10.1101/2021.03.19.21253971

Cited by 14 publications

(31 citation statements)

References 10 publications

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“…In this purpose, we defined several scenarios of simulation by modifying the corresponding parameters in the viral dynamic model. First, we increased the viral production parameter, , by a factor of 2, 4, 8,16, 32, 64 and 100 corresponding to observed increases of 1-7 value for different variants 2,10,11 . Second, we decreased the production parameters by a factor of 2, 4, 8 and 16 as well 4 to emulate the impact of vaccination 4,13 .…”

Section: Calculating the Average Probability Of Transmissionmentioning

confidence: 99%

Quantifying the relationship between SARS-CoV-2 viral load and infectiousness

Marc

Kerioui

Blanquart

et al. 2021

Preprint

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The relationship between SARS-CoV-2 viral load and infectiousness is not known. Using data from a prospective cohort of index cases and high-risk contact, we reconstructed by modelling the viral load at the time of contact and the probability of infection. The effect of viral load was particularly large in household contacts, with a transmission probability that increased to as much as 37% when the viral load was greater than 10 log 10 copies per mL. The transmission probability peaked at symptom onset in most individuals, with a median probability of transmission of 15%, that hindered large individual variations (IQR: [8, 37]). The model also projects the effects of variants on disease transmission. Based on the current knowledge that viral load is increased by 2 to 4-fold on average, we estimate that infection with B1.1.7 virus could lead to an increase in the probability of transmission by 8 to 17%.

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Section: Calculating the Average Probability Of Transmissionmentioning

confidence: 99%

Quantifying the relationship between SARS-CoV-2 viral load and infectiousness

Marc

Kerioui

Blanquart

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…A minority of samples originated from hospitals (6%). Most individuals (88%) were sampled twice and the median follow-up 2 duration was 8 days (IQR [6][7][8][9][10][11][12] days). Most samples originated from the Ile-de-France region (64%) and were caused by the V1 variant (73%), which reflects the state of the French epidemic at the time where the samples were collected [13].…”

Section: Resultsmentioning

confidence: 99%

“…RT-PCR have been reported to exhibit lower cycle threshold (Ct) values for V1 than for wild type infections [1, 8]. This suggests that VOC may be causing infections with higher virus loads but these analyses only included a single time point per individual.…”

Section: Introductionmentioning

confidence: 99%

Variant-specific SARS-CoV-2 within-host kinetics

Elie

Lecorché

Sofonea

et al. 2021

Preprint

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SARS-CoV-2 variants are causing epidemic rebounds in many countries. By analyzing longitudinal cycle threshold (Ct) values from screening tests in the general population and hospitals, we find that infections caused by variant lineages have higher peak viral load than wild type lineages and, for the B.1.1.7 lineage, have a longer infectious period duration. Linking within-host kinetics to transmission data suggests that infections caused by variants have higher transmission potentials and that their epidemiological fitness may depend on the demography of the host population.

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“…When analyzing variant-specific testing spanning from January to March 2021, we found that V1’s transmission advantage to the wild type was larger than that of V2 [8]. During April 2021, in at least two French regions, this trend appears to have shifted with V2 spreading more rapidly than V1.…”

Section: Discussionmentioning

confidence: 99%

The SARS-CoV-2 B.1.351/V2 variant is outgrowing the B.1.1.7/V1 variant in French regions in April 2021

Roquebert

Trombert‐Paolantoni

Haïm-Boukobza

et al. 2021

Preprint

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SARS-CoV-2 variants threaten our ability to control COVID-19 epidemics. We analyzed 36,590 variant-specific RT-PCR tests performed on samples collected between April 12 and May 7, 2021 in France to compare variant spread. Contrarily to January to March 2021, we found that the V2 variant had a significant transmission advantage over V1 in some regions (15.1 to 16.1% in Ile-de-France and 16.1 to 18.8% in Hauts-de-France). This shift in transmission advantage is consistent with the immune evasion abilities of V2 and the high levels of immunization in these regions.

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SARS-CoV-2 variants of concern are associated with lower RT-PCR amplification cycles between January and March 2021 in France

Cited by 14 publications

References 10 publications

Quantifying the relationship between SARS-CoV-2 viral load and infectiousness

Quantifying the relationship between SARS-CoV-2 viral load and infectiousness

Variant-specific SARS-CoV-2 within-host kinetics

The SARS-CoV-2 B.1.351/V2 variant is outgrowing the B.1.1.7/V1 variant in French regions in April 2021

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