Characterisation of vaccine breakthrough infections of SARS-CoV-2 Delta and Alpha variants and within-host viral load dynamics in the community, France, June to July 2021
François Blanquart, Clémence Abad, Joëvin Ambroise, Mathieu Bernard, Gina Cosentino, Jean‐Marc Giannoli, Florence Débarre
Abstract
We compared PCR results from SARS-CoV-2-positive patients tested in the community in France from 14 June to 30 July 2021. In asymptomatic individuals, Cq values were significantly higher in fully vaccinated than non-fully vaccinated individuals (effect size: 1.7; 95% CI: 1-2.3; p < 10-6). In symptomatic individuals and controlling for time since symptoms, the difference vanished (p = 0.26). Infections with the Delta variant had lower Cq values at symptom onset than with Alpha (effect size: -3.32; 95% CI: -4.38 to -2.25; p < 10-6).
Topics & Concepts
AsymptomaticSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2)Coronavirus disease 2019 (COVID-19)MedicineDeltaHost factors2019-20 coronavirus outbreakViral loadInternal medicineImmunologyVirologyDemographyVirusInfectious disease (medical specialty)EngineeringSociologyAerospace engineeringDiseaseOutbreakSARS-CoV-2 and COVID-19 ResearchSARS-CoV-2 detection and testingCOVID-19 epidemiological studies